Key doesn't operate central locking

Hi all,

I drive an 04 Astra Njoy Saloon, the original key no longer operates the central locking, I have to manually insert the key to open and close the car.

It looks like the battery is no longer making contact with the circuitboard, the plastic housing into which the batery sits is loose. I think maybe a bit of soldering might fix it, but I'm not adept and don't really want to try.

I got the car second hand a few years ago, and even then there was a piece of cardboard holding the battery against the circuitboard, but even this no longer works.

My question is - where would I bring this to get repaired (bear in mind, I work 9-5) - anywhere along the M50 would be handy. If it even CAN be repaired I suppose.

If repair is not an option, a new key. Where would I get it, and how much is it likely to cost?

Cheers guys, I've gotten some good advice here in the past!