This won’t help, but I have recently sold my 110 with a factory fitted roof (and bunks), I had done last year.
Dormobile carried out the work, in Romsley, Hampshire, over a period of three weeks at a cost of a few pence short of £3k.
Lessons learned from this experience are that I would probably get them to fit it to a roof, rather than let them have my complete vehicle, and that the roof wouldn’t have a sun roof in it , and that I would spend some money on getting the headlining completed.
Hope this helps.
I am sure there are roofs available from members, though.
Have you looked on the Dormobile UK web site?