Finally got round to buying a pair of ballasts to replace suspect ones...I hope the HIDs sometimes failing is due to the ballasts.Trying to remove the right side headlamp assembly first....
I removed the lower bolt, the top bolt and the inside nut. The assembly is now loose and will come out a bit, but it's jamming on something which is to the outer edge of the car. I can't see what it is and daren't fiddle any further, so I've put it back for now.
It's an 05 XKR coupe with HIDs and self levelling. Plus headlamp wash.
Further guidance much appreciated.

 

You will need to separate the washer jet mechanism from the lamp unit first before it will come out, you need child sized hands to do this. It is held in place with two tabs the need to be depressed.

 

This is what it looks like from beneath after I repaired mine.

 

Many thanks for the quick replyWill take a look tomorrow, I've got a feeling this is going to be on the hard/nearly impossible pile

 

I had to do this a week ago: the lights tend to jam on the jet wash down pipe and/or the bracket that holds the bottom bolt. The trick is to remove the jet wash unit by pulling it towards you just as the light unit is nearly out. You should then be able to jiggle the unit out.