blocked bath plug hole

BitterAndTwisted

Yep, bicarb and vinegar followed by a kettle of boiling water. That's after you've got to work with a crochet-hook or similar to remove all that shed hair tangled down there. I'd give the hair-removing cream a go if the bicarb and vinegar doesn't work. If that doesn't shift it I'd have a think about buying one of those pipe-snake thingys.

I would never, EVER mess about with caustic soda! It's dangerous stuff and so are the fumes. Very dangerous. That's not what you want anywhere near naked flesh or young children. The problem with using it is if it doesn't solve the problem you've got a pipe full of a nasty caustic liquid to deal with as well as a blockage. Doubly dangerous and not an attractive job for a plumber to deal with either.