If your gut feeling is that you don’t like the photographer then don’t hire them. Simple as. I’m guessing you actually want nice pictures out of it.
Steps for spotting a faux:
Stuff is blurry or badly exposed
They only conduct business from their facebook profile
Their prices are far lower than other photographers who look like they know what they are doing
They mention nothing about VAT
There is not at least half a dozen weddings shown in a portfolio (this might be tricky if they just put all pictures together)
They haven’t got a proper email address but use something like a hotmail or gmail account
Shots are taken with pop-up flash
Easiest would probably be if you posted a link with his facebook and you can get some input from us if you aren’t sure. As for finding someone you like, it can be tricky. Best thing is to google a bit and then call up a few of them where you like their style of pictures, to have a little chat to gauge what they are like. Nothing worse than to have a twatty photographer at your wedding. If they put prices on their website I would not expect what you want to come in at less than £1500 for a cheap tog and most likely a bit more than that. If you see someone charging less than £1000 then ignore as they are not going to be seasoned wedding shooters and unless you are out in the sticks somewhere less than £1500 should ring some warning bells.
Simple reason why price is a good measure of the quality of the photographer is that a good professional will not work for minimum wage which they would if they didn’t charge those prices. It seems a lot but often you get what you pay for.
Where in the UK do you live?