As I had a T5 Caravelle sat outside and a fairly basic T6 which I stripped out I spotted the holes in rear body for the hook so took about having ago to see if they could be added.
Parts required - Hook 7H5867615 they pop up on ebay for about £20
If you have plenty of dosh parts required - 7H0867625G (this should save you having to do the cut)
Tools required - Rivnut tool. I beleive although please check prior it was an M5.
Take the rear plastic cover off the upper rear ceiling.
On the left (passenger side) you will see 3 holes with no nuts in. This is where you will need a Rivnut tool. Install 3 rivnuts.
Next take the plastic cover you removed and using the template supplied here, print it on A4. Cut the middle of the hole out. Align the A4 sheet with the left end of the plastic cover. Mark out the shape. Cut the shape out (got angry with my as I seem to have the bluntest tools!) so you will probably be able to get a better finish but do not worry too much as the hook has a lip which covers the edge.
Refit plastic cover, install the hook with the 3 small bolts (again need to check what ones they are)
Done, now enjoy.