10×10, replacing a heavy but Cole can esque Yardman shed. Any go-to suppliers?

Prebuilt sheds can be expensive. Have you considered the diy option. Good old CLS frame, and OSB board sheeting.
You decide on door size, where the windows go.

First offing into joinery I did a course at the building and printing, and one of the tasks was to build stud partitions, sheet(osb) make a window frame and make and fit a simple door.
Nobody on the course had any joinery experience but everyone found it an easy task when they understood the criteria.
Tools involved was a hammer – In fact all 20 of us timed our hammer blows and the noise was deafening 😆 Jigsaw, handsaw, one chisel and lots of 4″ nails.

Where in Glasgow are you(approx)

Yes I have considered DIY and with long lead times currently its still an option. Watched a few videos but need to get a list of timber required and price it all up. Did that for a few items in BnQ today as a starting point but as I say need to work out what I need and quantities. Oh, and hopefully use a proper timber merchant to reduce prices somewhat!

Out Kirkintilloch direction.

Got my brothers wedding present, a shed, from the shedman in rutherglen about 25 years ago, 2 house moves and it now lives at our parents still a good shed. I got mine from Flemings in crosshouse Kilmarnock in 2004, new felt about 5 years ago, still dry and solid. Both places delivered and assembled on site. Paisley and inverkip respectively

If I was in the market for a shed…
https://gilliesandmackay.com/sheds/
Expensive? Yes – but you get what you pay for.
Based in Perth.

Came recommended on here before, if nothing else they are good for the wood.

https://www.stewart-timber.co.uk/product-category/garden-sheds/

I got mine from Flemings in crosshouse Kilmarnock in 2004,

I’ve been on his waiting list since June. I really should chase it up/order from somewhere else

Finding so far from limited research lead times are very long at the moment.

Prices from Stewart Timber etc don’t seem to be any better than B+Q, is this because accounts get better rates or the timber is just superior quality?

Is something like this a good guide?
https://wood-create.com/2018/09/27/how-to-build-your-own-shed-from-scratch/

Also concerned about the DIY route timescale wise- how long it will take/materials getting wet in the process.

Patersons of South Alloa / Falkirk.

https://www.patersonsgardenbuildings.co.uk/

Bespoke and stuff. As used by me and all my friends.

If I was in the market for a shed…
https://gilliesandmackay.com/sheds/
Expensive? Yes – but you get what you pay for.
Based in Perth.

I have an appointment here tomorrow morning, they have warned me that unless buying from the sale range which can be supplied in February, the lead time for all others is something bonkers like July.