Found a good shop in Bristol today with good selection.
Tried a blackstar studio 20. It was fucking great. Really liked both channels. The clean just has a tone control but it worked well with my guitar and the preamp section starts to crack when using a humbucker at high volume. Loads of tone variation in the crunch channel and more gain than I commonly need. I was quite happy just sitting there playing kinda forgetting I was amp testing which is probably a good thing. Happily when you max out the volume on the clean and crunch channels they are pretty much exactly the same volume (controlled with the master of course in the shop).
Also tried the 5W blackstar. The gain channel was really good, plenty loud enough for me and I liked the tone a lot, just as much as the Studio 20. Problem is that the clean channel is fucking shit. Cranked it to full and it doesn't have anything like the balls of the crunch channel. There's no master on this amp either.
They also had a Marshall DSL 15c which I would like to try when I revisit to take the Studio 20 into a private room where I can work the power section a bit. Decent day out.