do you have a local area fb group? it's a bit wheat/chaff, but I've had luck sourcing trades from recommendations i've found on there.
that, or if you've used any other trades you've got on with/had positive experiences with - could drop them a message and ask if they know anyone with X specialty.
Checkatrade vs Trust A Trader vs MyBuilder - any that are better than the other for some small damp repairs?