I put this in my new XJR thread, but I'm copy/pasting it here as well.

Ok, so I've already done something stupid. If someone could please advise me on how to get out of this pickle.

I was removing the differential fill plug with a small adapter and a ratcheting wrench, just like I did for both of the XJ8s. Apparently the XJR fill plug is much longer/deeper, either that or there is less clearance. While cheerfully ratcheting out the fill plug I realized the apparatus (adapter and fill plug) got jammed against a suspension bar of some sort. Since the wrench is ratcheting and not reversible, I can't re-tighten the plug to allow clearance to remove everything. It's almost laughable, but I'm stuck!

Unless someone knows a magic trick, I guess I need to know the most efficient way to move that suspension bar out of the way. What do I need to disconnect and how much trouble will it be to reconnect everything?

RESOLVED! -- Thanks to Convincor in the other thread. He recommended removing the two mono strut bolts and lowering the differential with a bottle jack, worked like a charm.