With a plethora of property searching websites and online forms to register interest, it is very easy to look around and not have to deal with estate agents in person until on the day of the viewing — but this is a bad move.
You need to go into the branches and meet them. Sure, they will pool you in with another 20 people that want to see the same place, but this is your chance to wave that mortgage agreed in principle in their face and make them put you at the top of their list.
You can look on the online property searching websites to get a gauge of who are the active agents in the areas you're looking for and to see what kinds of properties you can get, but a lot of the time they're either gone or the open days are fully booked.
Want to know how to get around that? Well, estate agents like Barnard Marcus have a special list of people that they show properties to before advertising them more widely. To get on it, you show how financially liquid you are and your mortgage agreed in principle.