I've had a horrible month of being completely strung out by a guy who quoted for this. Feeling quite stressed by it all to be honest and would really appreciate advice on who to use instead, as I think this may now be the only way forward 
Basically this guy wanted a deposit before measuring up - he had to drive a long way and the builders assured me it was a 3hr job to measure and template for the kitchen and utility room, so the deposit was about right.
Guy turns up and does template. Then we need to change the thickness in the utility room as the 30cm is too thick for a tap - so I email asking him to change it to 20cm and also to take off the splashback behind the range cooker, as it would push the oven out too far and so I have switched for tiles.
I asked him at this point to send out a revised invoice, before the stone was cut, so we could budget for the final amount. To my surprise he comes back saying that the bill will remain the same as he needs now to order more 20cm (there is already some being used in the kitchen). Rather than make a fuss I agreed to this and just felt we had lost a couple of hundred. I then realise he hasn't given us a VAT number on his invoice (new build so I could claim VAT back) only has his UTR number. I asked him if he wanted to claim the tax back with a letter from my architect or whether he could give me his VAT number so I could do it next year. He said he would provide this later, which I felt was dodgy.
Now he is saying that he hadn't added VAT on (he clearly had it's on the invoice under TAX @20% with a separate figure next to it under the total) so if we want a bill wit VAT it will be even MORE!
I've emailed him now and said in no uncertain terms he is getting the amount quoted initially or we will get someone else to do the job. Really angry and feel like a complete mug. Not sure if I have any claim via Trading Standards?