When I moved about two months ago, it went like this...
-1 week deposit to take the property off the market, plus fee for agency check, as soon as we decided we wanted it
-1 month rent plus a further 4 weeks deposit (making total 5 weeks deposit) handed over the morning we picked up the keys and handed over the signed contract.
They wouldn't take a cheque for the second payment, as it needed to be in a form which would clear instantly, so we supplied a banker's draft.
Vicky