In that price range you're looking like something like the Panasonic DMC-FT30 (around ?130), Ricoh WG-50 or 60 (around ?200, they have a more expensive WG-70 model at c. ?280), or Fuji FinePix XP140 (around ?180). The industry standard (if there is one) seems to be the Olympus TG-6 (around ?370). Of course there may be deals etc. I'd have a good look at YouTube reviews to see what they're like and if any fit the bill on what you want to do with it. Ricoh (i.e. Pentax) are pretty good and have built in macro LED lights, which is nice. I eventually plumped for the Olympus, but the Ricoh was a close second. Might be able to find second hand Olympus TG-4 or TG-5, both pretty good cameras.
Some also have extras built in like GPS location recording, tracking, and digital compasses.