I wondered if anybody has come across this one .bought 06 c max recently ,central locking unlocks using key and using remote but will not lock centrally with key or remote but will double lock if doors locked manually and keys turned twice or remotely.fuses look ok.suspect locking relay but cannot find it any help will be most appreciated

If you have a TIS disc then start with the wiring diagram on page 501-14-00-38. The Lock / Unlock relays are apparently part of the central junction box but may also be part of the GEM which is a dealer replace item (needs programming) at around £400 I believe