I don't know what is available in the UK, so rather than give you specific brands, I would rather give you what features to look for.
I have an old Travel Trak. It has an inductive dampening (AKA magnetic) system. Once upon a time, that was the rage. There is a cable mechanism that lets you change the load while you ride. I have since decided that is a silly feature since one pretty much picks a load and sticks with it, and now I have this cable that just gets in the way.
It used to be that a pair of squirrel cage fans provided the most realistic ride load. These are really loud, and I don't think they are common any more. I suspect that the hydraulic (AKA fluid) loads are really a squirrel cage fan in a sealed oil bath. I would go with a hydraulic load.
Riding a trainer can redefine what boring means to you. I would get a wider framed trainer as that will improve your stability. If your attention span wanders, you could fall over. So get a wide framed trainer.
Some trainers just destroy bike skewers. Some trainers come with a skewer for you to use, and some don't. If you need to get a skewer, a Shimano Deore steel skewer is just about indestructable. I have a now hideous Durace skewer that I used only one time on my trainer. My trainer destroys aluminum skewers, especially pretty ones.
Riding a trainer is noisy. Using a slick tire (smooth profile) makes the least noise.
There are now trainers that are interactive, and let you relive your favorite ride, or experience downloadable rides. The gym I belong to has 2 work out bikes with interactive features. This does make riding the bikes a lot more interesting. I think I am to frugal to buy a trainer that does this.
Come up with ways to stay motivated while you ride. It will be boring.