Dunno' ... it would be more trouble than it's worth.

I've heard of that one. I think it's only about getting some height
and clear line of sight or maybe getting the fob away from a jumble
of surrounding keys. Or ... urban myth.

I keep my fob separate. Lock the keys in, still have the fob.
So there are never any metal objects shrouding the fob.

I can usually get the car to unlock as soon as I step into a
section of the carpark, not the whole carpark. If not, I can
wait until I get closer.

 

Hello Gentlemen across the pond.
I haven't read the whole thread but thought I'd add my suggestions if you are agreeable.
The "plip" button fault arises because the carbon on the underside of the rubber pad wears over time and is reduced to dust and guck.
One solution used by a fellow enthusiast on the Engish version of this site is to canibalise an old TV remote for the key pad under the buttons. Cut them down to size and replace the ones on your fob.
There is also a guy on eBay here who takes the fobs and fits micro switches in place of the carbon pads.
I've had both of my fobs done and they are great. Working range is over 40ft away from the car.
The guy on eBay is called fingaz. Not sure if he offers international or not.
Look under:
JAGAUAR XJ8 key fob plip repair.

 

The particular remote used on this series is Ford based,
so the rubber pad is available new on ebay. Don't know
if they are genuine or knockoffs.

Then again, the fobs can be found fairly cheaply if you
keep an eye out.

 

I have a couple of brand new remotes for a 99 Continental, any idea whether they'll sync?