I did a search but couldn't get what i was after on this one.
In the lower pin the bolt moves with the door - therefore tightens as it goes.
I am guessing there should be an inner sleeve to tighten against and this has seized?
It does look a bit orange, but I am scared to strip it.

Wots wrong with it or wot is it not doing?

Hmm.. that made sense to me when I wrote it but yeah clear as mud reding it back lol.

Ok so the lower Hinge (not pin ?!?!) bolt secures the two halves of the hinge by going through the top half on the door to the bottom half on the body. the bolt appears to be making contact with the top half which is the moving part and therefore as you open and close the door the bolt gets slackened and tightened. This requires a bit of extra force to close the door – not too much the good wife doesn’t see it but for me the door just never closes and I always have to go back to close it…

I am guessing there should be an inner sleeve through the top half so that the bolt tightens to the bottom half and that this has rusted to the top half?
like No4 in this link https://www.realoem.com/bmw/images/diag_4gmb.jpg

Quick vid of a wurkin door hinge:

Freelander 2 Driver Door Hinge

Looks like the bottom bolt should not move when the door is opened or closed. It's locked to the car body bracket. Eye assume thread lock is used.

Thanks for that. Just thinking I'll strip a good'n and have a look
Could be a day or 2 but I'll get back with what I find.
Cheers.