I recently visited their factory in Cirencester (its a bear to find, BTW). I got to inspect some of their work for Healeys and other cars- they provide an extensive range of materials and seeing them provided a far better impression than the small swatches of leather, vinyl and carpet commonly made available. They'll send those swatches out if you ask.
It was well worth the visit (and I got to avoid an afternoon with my inlaws too so everyone was happy) and I feel that I'll be better able to choose colors and materials than I would have been otherwise. I spoke with John Skinner himself and got the factory "tour" and was able to discuss things with them. They seem a very competent operation and dedicated to producing a good quality product.
I wasn't able to see a full interior since those are made to order, but I did get to look at some Healey pieces and they looked very nice, but they weren't actually in a car to allow their fit to be judged....
I'm not competent to assess whether they conform to concours standards either, but if that's your inclination they should be able to tell you whether their work conforms to orignal specs or not....