It's too bad you're in the UK because these are my fav and probably only available here... but for any US girls, I LOVE these! Just order one size up bc they run small:
https://www.target.com/p/bematernit...-15802730#prodSlot=large_1_9&term=bematernity
They are thick and definitely not see-through, and the belly band part of it is contoured really well so it's made for an actual baby bump, rather than just extra material. And there's a little cross panel thing in the back that makes them really comfortable. AND I never have to constantly pull them up all day... they stay in place. Seriously I love them... if you couldn't already tell, lol.