reverse light not wrking

[just vaux trev]

rewired all lights after fitting c20xe with full mk3 astra gsi loom got all ligts working apart from reverse the wiring is all right as light works when i take the switch out the gear box and press it so the switch also seems fine i took the top plate off the gear box and could see or feel no fault but then i doubt i would know what to look for ay sugestions as to what could be at fault could it still be the switch?
thanks in advance
any details on how the switch ect is engaged would also help:thumb:

[just vaux trev]

sorted (it was the switch)