C30 central locking not working when cold

[Herbs]

My sis in law has had this problem twice in the last 2 weeks where both remotes do nothing when trying to unlock the car. It unlocks fine with the key and sets off the alarm - starts and drives fine so not a battery issue.

When the weather is warmer it works fine as well so i don't think it is fob batterys either?

i have had a quick look online but nothing specific for the C30. The door harness appears to suffer problems on other models but does this apply to the C30 as well?

any suggestions gratefully received.