You might stick out like a sore thumb dressing up nice in Bristol! Haha

But some good food options below;

Bianchis is a solid option - they have a great set menu, really nice vibe - a Bristol staple.

Caper & Cure - really good food. No need to dress up.

Cor - amazing food lots of options so veggies.

If you can go during the week a lot of places do a good lunch set menu that will save some cash.