Won't replace a "real" wetsuit when it's actually properly wet, but if you need a cheap and cheerful thing to stay a bit warmer when it's merely "moderately moist" maybe this has a place?  https://www.lidl.co.uk/en/p/summer-fun/mistral-men-s-short-wetsuit/p42112

Worth looking on Facebook marketplace for stuff like this. There are always loads of wetsuits on there, some very cheap, some local, some decent. Occasionally, all three together!

I prefer the "dungaree" style wetsuit (think they're intended for windsurfing) worn as an undersuit for moderately wet trips; if your upper half isn't likely to be getting prolonged immersion you can dispense with the jacket and wear a fleece instead for easier movement. Picked mine up for something daft like a fiver on fleabay...

We got some excellent 3mm full suits by the name of " Hot Tuna " from Sports Direct ?28.00. What I/we could do with is some not expensive wetsuits trousers bottom style if anybody knows anywhere ?. I have found some but they are quite expensive !

Plenty of 'long john' (sleeveless wetsuits) second hand on ebay and Facebook marketplace at the minute from ?5

Not so much available for trousers...