Quick & professional service though costed double the quote

Convey Law turned around the conveyancing involved with the sale of my property in record time (three weeks from start to finish!).
Their information pack was well written, comprehensive and to the point. So were their emails.
It was extremely helpful that I could monitor the progress by logging in online.
As I am based in Australia it was great to be able to do everything online (with the exception of signing the contract hard copy). It saved a lot of time.
Though I was surprised at the end to see that the invoice was double the amount of the initial quote. For instance, there was an additional £20+VAT for each query raised by the purchaser lawyer, who had raised about 20 questions. That was annoying especially considering that to most of the question I provided the answers and some queries were of trivial nature and required a one liner for an answer.
Also I hadn't realised that I requested the no sale no fee option, so I was charged an additional £48.
Great service but not as competitively priced as they market themselves to be.
Still I would highly recommend them.