Looking at getting a sleeping bag for the summer, which will mainly be used for events rather than remote backwoods riding. I haven’t camped since I was a kid, so I’m not exactly sure what to go for.

Theoretically, I only need a 1 season bag, but I’m concerned that a) if the temperature drops (as it’s wont to do in the UK during the Summer), I’ll be too cold and b) I tend to feel the cold more now that I’ve lost a few pounds.

Am I better going with a cheaper 1 season bag and a silk liner, or just going with a more expensive 2/3 season bag?

I one of these a few weeks ago, that seems to be a decent buy:
Snugpak

Use this guide to determine if your chosen bag will be warm enough for you:

“Upper Limit — The temperature at which a normal man can sleep without large amounts of perspiration whilst having the hood and zips open and arms outside of the bag.

Comfort — The temperature at which a normal woman can sleep comfortably in a relaxed position

Lower Limit — The temperature at which a normal man can sleep for eight hours in a curled position without waking.

Extreme — The minimum temperature at which a standard woman can remain for six hours without risk of death from hypothermia although frostbite can still occur.

For the purpose of these measurements, a “normal man” is assumed to be 25 years old, with a height of 1.73 m and a weight of 73 kg; a “normal woman” is assumed to be 25 years old, with a height of 1.60 m and a weight of 60 kg.”

I prefer the 2/3 season bag, easy to unzip and vent, than lay curled up shivering.

Cheers all, think I’ll go for a 2/3 season bag.

same as dnf, for your purpose buy something a bit more than you need, it’s better to be too warm and opening zips, than too cold with no options other than trying to get warm by putting more clothes on. I hate liners, because I get all tied up in them, although I do tend to toss and turn alot!. Also, in your case, probably go with a synthetic bag, you can stick it in the washer, they’re quite heavy and bulky, but that won’t be an issue I presume, they’re a bit more practical and cheaper than feather down.