2004 Vauxhall Zafira key fob not working

Right my question is this:

The circuit board park of my zafira key fob is clearly damaged as it had a rubbish solder job done on it previous to me buying it. If I buy a new fob case with circuit board, will it just be a caesarian of synching it to my car as the transponder chip is still in the key section - and I would just be clipping the replacement fob + circuit board (which just opens/locks doors remotely) into the key section. ..?

Currently, the transponder chip is not 'communicating' with the car but could this be to do with the badly soldered circuit board?

Also then, if I buy a replacement fob + circuit board, and it still doesn't work, I can preaumay 'just' get the key (the chip) reprogrammed to the car?...

Thanks in advance - this issue is driving me nuts as currently, the fob buttons don't work (for obvious reaaons) and so I have to use the key in the lock but this then sets the alarm ofF. ..

!!!