Long sleeved jersey

My go to is a Ground Effect Rock Lobster.

Or a Galibier Trail Jersey.

Not exactly an answer to your question, but another option: you can get summer sun protection sleeves, which will provide a degree of protection from brambles (as well as the sun). I've got a few sets, and they vary in weight (and hence bramble protection). Most claim to be SPF 50+ if that's of interest. They're also pretty cheap.

Search for "summer sleeves sun protection" on Amazon and you'll get loads of options.

I'm also interested in the answer here.

Got a bit warm while I was out on Thursday and figured the problem was twofold. Black top that is also a bit heavy.

I'd love a nice grey long sleeved top with pad friendly cut on the sleeves... and not have to pay fifty quid plus for the privilege.

I picked up one of these in the sale. Not the greatest fitting or looking, but great arm protection, which is more important

https://www.polaris-bikewear.com/polaris-bikewear-overland-long-sleeve-jersey.html

I really like Setup jerseys, really nice cut and wick amazingly well. And £25. Tick all the boxes IMO

Try something non flappy ? I have been wearing one of my le col aero jerseys and they have the advantage of being skin tight and not flapping in the breeze

This, but in the sale for£30 not £75

https://www.rapha.cc/gb/en/shop/mens-trail-long-sleeve-technical-t-shirt/product/TLT01XXSOA

I bought the sand one, it takes 2 washes to get regular mud out. Dries super fast, a bit loose

I have a specialized white/ grey long sleeve top. Not as light as the Rapha one, just as tricky to clean

https://www.specialized.com/gb/en/mens-trail-long-sleeve-jersey/p/216727?color=1000107513-216727 like this but grey.

A

As above,  the technical trail tshirt from rapha is amazing.  Really really lightweight and is my go to top for the summer for the same reasons as the op. The greenery is nuts at the moment

These are pretty light:

https://www.altura.co.uk/products/altura-kielder-mens-lightweight-long-sleeve-cycling-jersey

Another vote for the Rapha one. Very good

I bought one of these in the Wiggle/CRC sale and was so pleased with it, I bought another one in a different colour

https://saddleback.co.uk/products/troy-lee-designs-22-drift-long-sleeve-jersey?variant=40537441370197&currency=GBP&gad_source=1&gclid=CjwKCAjw7NmzBhBLEiwAxrHQ-RPIlyoAxMn2jQfrSbp5lkSjSkBgO-g_cOe-4ojbHUnjnieLYe06JhoCCloQAvD_BwE

Endura Burner Lite is my summer jersey of choice.

I bought a Troy Lee Jersey which was long sleeved but the material was kind of perforated like a tea bag. It might even have been a MX jersey but it was nice and cool.

Running tops. Like this. Very light. Breath well. Good sun protection. TCA Men's Stamina Long Sleeve top. £20 on Amazon. Various colours. Not good bramble protection I suspect. Good in heat and good bramble protection may be mutually exclusive.

Used last year in 40C temps in USA. Dawn in Mojave desert

For brambles, the Rapha 3/5 sleeve one is good. The shoulders/sleeves use a tougher, woven fabric than the main body, which is high-wicking, jbitted polyester. Obviously your forearms are still exposed, but only a bit of them, but your sholders and elbows and above are protected by relatively tough fabric. Come up regularly on Sport Pursuit at roughy 50-60% of RRP. The main fabric is, I think, the same as the Rapha Trail Tee and a pretty good balance of cooling and wicking.

They also do a lightweight version of the tech tee, but haven't used that and I suspect it won't play nicely with prickly shrubs. I wouldn't say the straight Rapha Tech Trail Tee is that light fwiw, not heavy by any means, but nothing extraordinary, basically a nicely cut baselayer-type tee with a Rapha band on the sleeve.

Other than that, the 'problem' you have is that mostly LS jereys are intended for winter/shoulder season use, so tend to use a thicker fabric. The best really light summer tee I've found is the lightest version of Patagonia's Capilene Cool, which is thin, but problematic when snagged on brambles - holes easily ime and, of course, is a tee rather than long sleeved.

I wonder about lightweight trail shirts, if you can cope with looking like some sort of self-consciously stylised gravelista weirdo, wouldn't need to be cycling specific.

7Mesh Sight long sleeve is the best top I have for these conditions. Bought in the sportpursuit sale a while ago.

Just bought an Eyra long sleeve jersey using the Tweedlove discount 20% off code

very impressed with the quality

Thanks for the suggestions, I’ll check them out later. I’ll possibly try a few different options.
The current jersey’s I have are Endura both are heavy and ward off the brambles, they are both covered in snags but still fit ok after 5 years, but are too heavy for current conditions.

Rapha were mentioned several times, how do they size up? I’m usually right between M & L, some brands it’s medium other it’s large.

I really like my Context long sleeved jersey. Got mine in white, which helps in the sun and its got a strip of black mesh from the wrists to the hem, so nice and airy.

Washes well too, no stains as of yet!

Rapha were mentioned several times, how do they size up? I’m usually right between M & L, some brands it’s medium other it’s large.

I'd say they size pretty much close to size. I'm a medium in pretty much everything - bar stupid Italian road kit - and the Rapha medium trail kit is a really good fit on me, though just hinting at being tight across my shoulders, which are a little broader than they ought to be relative to my chest/waist. It's hard to say, but I guess if you're at the larger end of medium, a Rapha L might work better, I guess.

Another vote for Setup here. I run hot and and am sweaty sod. It wickes well and dries almost straight away on a long downhill.

I would buy another one when needed.

I picked up a Strava LS top in their sale and it’s pretty light weight but enough to keep the dreaded midge at bay but cool in warm weather

DHB Trail Drirelease. I’ve used it maybe 10 times now, excellent, though I’m not sure of its longevity, but its lasted at least 5 washes and still looks new, unfortunately no longer at the £15 I paid, though could be still available at House of Fraser etc.
https://www.dhbsport.com/collections/cycling-top-men/products/dhb-trail-long-sleeve-jersey-drirelease

I got one of the Polaris jerseys with the snag proof sleeves.

I’ve been out with that, orienteering long socks from Decathlon, knee pads and gloves. I can just ride along without worrying about nettles. Haven’t hit any long brambles yet but I’m sure I’ll be fine.

Currently £18 if they have your size.

I got one of the Polaris jerseys with the snag proof sleeves.

Rapha were mentioned several times, how do they size up? I’m usually right between M & L, some brands it’s medium other it’s large.

I'm reliably a large in Rapha. 6"4, 92kg, visible  tummy, 38 actual waist but 34 inch waist in most trousers. Perfect mamil 😢