I have an 81 XJ6 S3, with a sunroof than can both go back as most do, but also tilt forward/open the rear. Handled with the same switch and relay(s?) that I can hear and feel click sitting in the roof to the right of the inside mirror. My friend has a much more posh 85 VandenPlas XJ12 but he says his sunroof can only go back, not tilt forward. I suggested he looked at the relay(s), but he has no relays in that area. Does anybody know which type of sunroof was factory and where relay(s) are?

 

The slide-only sunroof, such as your friend has, is the Jaguar type. It shared the power window relay.... which is at the extreme RH side of the dashboard.

Your slide-tilt sunroof is an aftermarket installation (common back then). The details of the switching circuit will need to be discovered by you :-)

Cheers
DD