The Ultrascale website has been offline for over a month due to webhost/server problem. It's not going to be resolved any time soon. You have to telephone David Rogers direct if you want to order anything.
Sharman "B" profile wheels are almost the same overall width as the "A" profile, differing only in flange thickness and depth, and don't exceed 2.3mm. The sample B-type I have come out at 2.15mm, and I think it's possible to skim the backs of the tyres to reduce flange depth and height down to P4 profile, i.e. 2mm width.
Markits are no longer available due to the death of the owner earlier this year. There had been talk of his widow trying to restart the business but I suspect that's unlikely - it was a considerable undertaking for a one-man band, and the knowledge to run it properly and develop the already extensive product range died with Mr. Arscott. The only place you'll get Romford/Markits wheels now is on eBay, and most of those will be very much secondhand, stripped from old models.