The Estate Agents are trying to find out if you are a genuine buyer, so they will want to know that you are aranging your mortgage without delay. This is perfectly normal, as the seller won't want to stop marketing the house unless you are serious buyers. Once you have made a final decision on a lender, they will ask for a survery to be carried out. meanwhile, the solicitor will be checking title on the property and carrying out local searches. To be honest, if you were buying my house and hadn't started shopping around for a mortgage after a week, I'd be getting edgy too, as the morgage application process can take weeks.