2005 Astra cental locking problem?

My car battery died at the weekend, had it tested by the AA and he suggested buying a new one as everything else seemed fine. So after changing the battery my central locking now does not work on the key fob or by the switch in the car and the boot is permanently locked (got in with manual over-ride). Have checked all fuses and they are all ok. Any suggestions?...does the key need reprogramming to the car?.. if so how do you do it as its not the same as the 1998 - 2003 cars?