Realised I hadn't followed up on my review.
Company:
Website has lots of variations of T6/5/4/2.5 etc, and different convertors, so should be able to match almost anything you have.
Mine was in stock, and arrived in a couple of days.
Product:
Can't comment on VFM, as I am not sure that anyone else does a side-elevating roof cover, so can't really compare.
Seems well made, robustly put together and well sewn. It is a stiff foil-covered bubble type of material with enough rigidity to stay in place and not flap about.
Fits snugly around the roof. It helps (me being a short@rse) to have a step to attach it; for these side-elevating roofs do the front first!
As the side panel has to slope inwards I sometimes need to push the top half in towards the canvas; I use a trekking pole for this.
In use:
Makes the inside much darker, but can't be helped. Cuts down on outside noise considerably.
We have used it in April and May so far with some very cold nights; the van is noticeably warmer with it in place.
Much reduced condensation on the canvas.
Once you have figured out how to roll it up it is relatively easy to put away.
Size for storage is shown by
@PDNC above; it's not a thin wrap you can scrunch up into a bag.
In summary:
Excellent product, makes colder weather camping much more comfortable. Not currently using it, but will be back in the van come September.