Pug 307, flat battery and central locking woes

[princeperch]

I've got a 2004 307. The battery is knackered according to the AA man today. Fine, I shall replace it. The problem now is that the car won't lock at all with the fob, and only th front doors lock with the key, the boot and rear doors are still open.

Not overly bothered as the car is parked outside my house and I can't see it, but this is east london.

The car cost 390 quid so as you might expect, no handbook.

Any tips on how I can't get the car locked up? Or maybe it's for the best I can still get into it given the state of the battery?