Thank you

Any idea which relay position within the fuse box? If I'm to buy one, are all relays the same?

This car has 5 fuse boxes but presumably this would be in the fuse box in the trunk that is a foot away from the connector, right?

Any idea what format of connector that is? If possible, I'd rather build a harness to plug into it instead of cutting the plug-end off the wires.

 

Fyi, brown-green wire is + direct to the battery, black is obviously ground

Can't get anything from the yellow-blue wire as of yet...

 

I am travelling so no access to my car, but:
The relay box is indeed the rear one, google on it and you find the (probaby empty) space. I think it is called accessories.
Then just pull one of the other relays as sample, its a basic one.
I could not find the correct connector, so used insulated spade connectors to slide into the excisting male pleg connectors. Works ok and is reversable.

 

Got it - stick a relay in position #6 in the trunk fuse box and the yellow-blue wire goes to 12v when the car is on

 

They must have been very thin and long as the connector seems to be very deep (over 1cm) before reaching the connectors. I'm presently trying to figure that bit out - last piece to the puzzle :-)