Done a couple of quotes via email and quoted them off streetview (and got them). I get the number, road and find the house. I then ring them, describe the house im looking at and ask if they have an extension or conservatory at the back. They give the answer and i give them a price.
Ive found doing it this way has saved me time, fuel & im either spot on or over priced from what i would have quoted if i was walking around the property.
I dont tell them im doing it this way. If they seem though they want a price without me going to quote, i would actually go out and quote it in person and add a little for my troubles now