When employing any trade, my advice to anyone would be to ask family & friends for recommendations as well as contacting any trade who's been on SF for a decent period of time.
(The idiots get found quickly & disappear).
Ive been to see a job today where someone had used my business name via one of these "Check a trade' type sites.
A complete and utter bodge job and left the customer in a mess.
Any decent trades person will not need to chase business via these sites.
I asked the customer if they could describe my van. Was told a plain white van. Mines silver with sign writing !
Final tip, don't take recommendations from Facebook etc.
Just be careful. Any respectable trade will be happy to give you a card with a land line and address along with a written estimate/quote.
Be aware, don't get ripped off.