I finally got time to install the rear back heater pads today - note this is for an Estate
Removing the rear backrests is not difficult, first remove the squab by pulling up ~8 inches from the door, remove 2 10mm bolts between the 70/30 fold at the hinge, one in front, one accessible from rear then a few torx bolts and the seats pop out - they were quite a bit heavier than I thought though.
Installing the 70 side heater pad was quite easy, using a wide bladed screwdriver slide it gently into the join fold on the back of the seat towards the bottom and prise the sealing strip up, once partially lifted the screwdriver blade can be slid underneath the remaining sealing strip to pop it open. The heating pad can be slipped up inside the seat cover from the bottom rear without difficulty - make sure the wiring colours for the pad match the squab, mine were blue and black outer sheath colours respectively to match the squab outer sheath colours
This image shows the back of the 70 side with cable protruding from the bottom rear:
http://i1285.photobucket.com/albums...aguar X Type Rear Seat/70Seat_zpsc72f0cb8.jpg
You can see the sealing strip and if you enlarge the image can also just about see the slot it fits into
Unfortunately the other photos I took are unusable *but* I hope the description given is sufficient, if not, pm
Installing the 30 side was a completely different matter, there is insufficient room to install the heating element from the seat bottom rear so I opened the side furthest from the top catch, slipped the pad in then pulled the cable through the bottom opening, this proved much easier.
To get the cables out I cut a small slit into the bottom fabric and pulled the cables through, this is hidden when the seats are refitted - leave enough slack in the cable to allow the backrests to fold forward
Initially I tried to use a wide blade putty knife to remove the sealing strip - don't bother as you will need a stiff wide bladed screwdriver. Resealing the seats was by folding the sealing strip back into the slot it came out of, when pressed into the groove you should hear clicks as the tabs engage. Note the 30 side was tighter and more difficult than the 70 side requiring more brute force - I had already expended the ignorance in working out how to do the 30 side!
Refitting the rear backrests was easier with both installed as they supported each other, the top torx on the bottom brackets are obscured by the padding at the bottom of the backrests so be careful in aligning the brackets lest you cross thread a bolt. There is a bracket covering the centre pivot which is not obvious from the diagram in the manual, fold the 30 side down and side the bracket into place then secure with the top bolt but do not tighten until bottom bolt has been tightened
Once the backrests are sorted the squab can be refitted
All that is left is the wiring which is another days challenge