Belt driven with magnetic resistance is what you want to look for. I recently bought a pooboo bike* off of Amazon and have been happy with it. I switched out the pedals so that I could use my bike shoes, and it was very straightforward. Not sure if you can get this in the UK, but the price hovers around $275 US. Amazon UK may have better options that are affordable.

When I was figuring out my at-home setup, I saw a lot of people talking about Sunny and MaxKare bikes, too, but when I was looking, the ones I liked were all going to take months to arrive.

*That’s not an affiliate link. I don’t make anything off of it. Definitely buy what’s best for you!