Toby, Andy,
What comes up on a VCDS scan?
Has the key fob been synchronised post battery change ( either key fob battery or Vehicle battery) failing that has Steve’s
@Birchall guide been followed to programme the fob to the CCCU as the key fob may we’ll be ‘new’ and not matched to the CCCU.
If it doesn’t match to the CCCU then pleases add pictures of the said CCCU and the remote half of the key fob as it’s possible they’re not compatible with each other.
This could be a simple fix as this system isn’t the most sophisticated of components to swap should one of the items in the circuit be at fault.
Whatever you do, do not call an auto locksmith.
Kind regards,
Tom