trailer wiring

[SteveC]

I'm planning to wire up my VR6 for a trailer, does anyone know of existing grommets or holes in the tail where I can feed the wires through?

otherwise the spare wheel well looks like the best place to drill, but seems to be double skinned

does anyone have any knowledge or experience that would be helpful?  (aside from cardigan & slippers or drives with a hat on jokes)

thanks