Ah-ha!
Got the multimeter out today and patiently pinged everything through. Upon doing so, I discovered that in turning the headlight over I had foxed myself and swapped out the high beam bulb instead of the low beam. I hadn't thrown the old bulb away - because I thought it looked like a good one - so I just reversed my error and swapped the real blown bulb.
Crisis averted! And some kind of lesson in hubris; it will teach me not to claim I can change a bulb again. 😉
Good Morning Graham,
Welcome, good to have you on board.
As you have found already Jaguars are a real pleasure to drive.
If you have any Photos please feel free to post them.
Kind Regards,
Julie.