I'm not too sure how it works in the US, but it sounds (from reading posts here) that you go to a letting agent, tell them what you're looking for and then they search for properties for you and get back to you with a few different ones and set up viewings for you?
It doesn't work like that at all in the UK. As maat1976 said, the agencies work for the landlord, not for the tenant - all they care about is getting a tenant for a particular property... so it's up to you to find the properties you like, across a number of different agencies, and then you contact each one individually to arrange any viewings.
So, the general flat/househunting process in the UK is:
- You look at the windows/websites of the letting agencies and make a list of the properties from each agency that you're interested in
- You contact each agency yourself, telling them which property of theirs you would like to view and they will arrange a viewing for you.
- You meet the letting agent for each property when you go to the viewing
- When you've seen each house, you decide which one you would like to rent and contact the letting agency who is responsible for it to see if it is still available.
- If it is, then you can start sorting out the paperwork with them. If not, then you'll have to re-evaluate your decision and either try to rent one of the other houses you've viewed (maybe with a different agency) or just start over and continue with the house search on your own.
So, you can see why it's difficult to try to contact agencies to help you before you are in the UK.