Interior lights not working

[JonesyB5.5]

Can anyone give me pointers as to why my interior lights don't work when opening any of the doors? All door locks are working fine, I've replaced 2 of them as the microswitches had failed. The light works off the button on the light itself and strangely the boot lid light works too when opening tailgate. Does this point to the CCM? There is no water ingress but I haven't actually checked the CCM itself. Any thoughts appreciated as it's annoying.