OK, so I have the old oil changed as the sleazoid dealer I bought form didn't even change 18 months old(or more) oil.
Go to leave work, and click-dead everything just after opening windows with the remote trick. A few minutes and I see the negative battery post cable clamp is broken. Fix that temporarily and now the e brake won't release.

Find a vid online and how to reset it which worked fine but all settings have reset. No one touch window closing and the like. One nice bit was the fuel cap code that's plagued me is gone and hopefully forgotten. Maybe it's easier tame a real Jaguar.

 

Even with that bad cable, betcha that battery is toast too. 18 months without fresh oil? Kitties don't like that kind of neglect. A real one would show you her claws...too late by then.

 

It's a lovely looking AGM battery but could be ancient being nice and cuddled in the trunk. I'll look for a code, Exide so a decent brand anyway.

And this one sat for 18+ months so no miles on old oil, just 200 or so I put on.

 

Even a slightly weak battery will throw electrical systems off, and have you chasing ghosts, either with codes in unrelated systems, or just plain nuisances. Test it before throwing any parts (ok, you do need a new cable) at it.

And, BTW, it might be a 24 month battery, which means it time bombed while snuggled in the trunk.

 

So I got my 1st parts shock-$60-80 for a new negative battery cable...! I think I'll do a new terminal as my cable looks new still w/10k on it.

And time to call ghost busters. Do I need to reset preferences somehow such as 1 touch auto up windows, etc? Or does it need a reflash?

 

And is there any harm in going aftermarket on a battery cable? Seems innocuous enough.

 

I wouldn't hesitate to go aftermarket on a new battery cable. Just make certain it is stout enough....

 

Got one, 4" longer and slightly thinner but such a short run it should be fine.

 

Thinner is not a good sign. Make sure its equivalent to factory. I would look on eBay for a used OEM cable. I wouldn't trust aftermarket...

 

There is very little aftermarket for Jaguars in general. On top of that, these cars have a number of "ground switched" circuits, so whatever you do, please don't change resistance characteristics by using higher impedance (resistance) wiring (the thinner the cable, the higher the resistance) to chassis ground.

The only true break you can expect $ wise, is the fact that SOME parts carry a Ford part number cross reference (detailed lists are within this forum).

In this case, I am unaware of any Ford model with a trunk (boot) mounted battery nor equivalent ground cable.

Check your local listings on Craigslist for a cost effective used part from a part out.