different defender truck cab backs?

I'd post photos, but im on my phone and can't work out how - so words will have to do.

Some defender pickups (open back) have the sides of the back in the same style as defenders with seats in the back, and the rear is joined to the cab.

But some have a small gap between cab and rear, and the rear looks slightly different styling, as if it would just bolt on and off.

Can someone outline the differences here, pros cons, changing between them, ages etc?

Thanks

the centre bulkhead is different.

usually its ones that have got hicap backs that have the two piece utility bulkhead

the utility back bulkhead is much more desirable if you have a pick up imo as its much more versatile - for example if i had one i would be able to rip the tub off and put a tray back(as in aussie ute style not the challenge style) on to make a much easier demountable camper build.

Yes i could cut it but it would look bollocks.