I fitted the same unit, works great, but had to modify the boot catch by putting a hole into to allow the pull rod to attach to it.
Didn't bother fitting the tiny switch and relay.
Instead I run a wire from fuse 1 (main fuse, 60A) with a 10A fuse in line to an industrial rated pushbutton (10A rated) fitted in my centre console, then run from the switch to the engine bay. The wire then was passed through boot loom conduit and up to the solenoid. The return earth wire is just bolted to the boot latch mount, as it is at 0 volt or earth potential.
Easy to wire and works superb.
Sundance
Here is the hole in the catch