I have done a first time removal of the front OS (UK) wing on my XJ8 (ear 2000) but the last two bolts at the very front were stiff and they broke out the captive nuts which turned out to be cylinders that have a rim that fits on the outside with the cylinder fitting inside the box panel into which the bolt is fitted, Very neat as I suspected I would have to break open the box to stick on two more nuts. I cannot however find a reference for them to replace then. Can anyone tell me what they are called and better still a part number.

 

I can answer my own question now if anyone who has the same problem comes across this. Apparently they are called bolt serves and are available in a selection of sizes and you need a special tool which looks a bit like a rivet gun to secure them. I found self tappers did the job fine at a few pence each.