Rear light bulb holder

[bramling]

I need to replace the rear light bulb holder on my Berlingo van (2008) getting the light cluster off and removing the bulb holder from the light cluster is not a problem, but the wiring loom clips inri the back of the bulb holder and is held in by a spring clip that is difficult to get at. Can anyone tell me how to unclip the loom without breaking the plastic holder. Any points appreciated...