Disco TD5 Auto electrical issues

Hi all.....I haven't been on here for a long time but just hoping someone can help. I am at my wits end with this problem and need to get my disco NCT'd {Irish equivalent to MOT} My problems started in February when I got the flashing M+S lights on the dash and gear selector console. I plugged in my Nanocom evo and got fault code P0705 position switch monitoring. I cleared the fault and M+S lights went out and stayed out. I started it up, put it in drive and noticed that the instrument pack still displayed Park even though drive was selected. I went through all the gears and still displayed Park. Took it for a drive to test the gear changes and it changed gears correctly. At this time I went to let the window down and nothing happened. I tried all the other windows and no joy there either. I then went through every system to see what was and wasn't working. I determined that the windows front and rear, front foglights, intermittent front wipers, rear wiper, heated rear screen and with ignition off the fuel flap doesn't function.....I condemed the xyz switch as I thought that because the rear wiper is supposed to operate when reverse is selected and didn't, that this was the problem. I got a known good replacement which I tested myself in the vehicle before it was removed. I fitted the switch and problems still exist. Plugged in the Nanocom again and no faults present in any system. I noticed while doing this diagnostic that in the BCU inputs body 1 that the Park/Neutral switch is reading as off when in Park or Neutral and reads as on when reverse is selected. However, in body 2, it shows park or neutral as on when in park/neutral. So, a contradiction there....I have since discovered that if I pull the earth lead off the battery or remove fuse 13 from the engine bay fuse box and connect them back up again, and switch ignition to position 2, everythings works as they should. The gears display correctly on dash and selector console as I cycle through them and all the other systems ie windows front and rear, rear wiper, front intermittent wipers, fog lights etc all work but as soon as I turn ignition to position 3 and start the car, all the problems return.....Has any of you very helpfull guys or gals out there experienced a similar problem with your disco td5

Sorry everyone for the chapter of a book I've just written but I'm desperate

Thanks all.....

Have you tried an Auto Transmission specialist, they are more used to checking this sort of problem and if the XYZ switch is faulty, ask them how much to clean and re-build rather than replace, tis cheaper ...

I don't believe the xyz switch to be the problem.....Like I said, I tested it in the donor vehicle before it was removed and since fitting it, I don't get the flashing M+S lights and no fault codes stored in the EAT ECU or the BCU, except for the contradiction in Body 1 and Body 2 inputs, but this is not logged as a fault by the BCU :crazy:....What I would like to know is has anybody else had similar problems with their disco and what, if resolved, was the problem?

Please, somebody else has had to have suffered similar issues...

Thanks all