Might be worth a google search. If I remember correctly you need to drill out the plastic to get to the solenoid. You can fit an older style solenoid,but you've got to find the live feed out the 3 wires or run another live feed on a switch.
Changed wheel bearings on passenger front as it colapsed yesterday. Took it out for a test drive and noticed a front prop uj gone. Seems like my disco going though a rough patch:)
Yeah thats the one.you've got an anti tamper one.if I remember correctly Its got 3 wires because of the immobiliser system. There is a thread on here somewhere about changing one like that.
Solenoid would be the main and first thing to look at. You can get away with cleaning it,but as there only a fiver to replace its easier just to go with a new one.
Can't help with the elctrics, but if you search there a few threads on fitting different seats. Easy job you just need a square of metal thick enouh to take your weight:)
Megasquirt might be an option for the rover lump. Mates got it fitted to his and the improvement was like night and day after he got the ecu map fiddled with.