If you are on a common supply (the tap on the pavement feeds more than 1 house) they will fit it at the point of entry (where main enters your house), if you have your own tap in the pavement then they will fit it there, this takes 2 minutes if you have an ebco box or similar there, if not they will dig up pavement and fit you a new tap with a meter.
If you have the common supply they will fit it inline at point of entry by your internal stoptap, this should take no longer than 30 to 40 mins.
If you are on a common supply outside and have multiple points of entry inside you will not be able to have a meter, you then will have to ask for an assessed measured charge.