my key doesn't work the central locking anymore
 

hi. could anyone help me by telling me where i can get my key sorted as it doesn't work the central locking i have changed the battery not realizing there were a specific way of doing this now i have one key that doesn't work and the spare key could do with a new battery being put in but can't seem to find anywhere that will sort it out for me need it in sorting the loughborough area if poss. :confused: :wonder:
thanks