Hi Paul,
The only problem with the Wilwoods is they have no dust seals so they won't be ADR legal. Plenty of people have used them on the street down here but as long as you know.
An alternative caliper that will meet the ADR spec can be supplied by Hi-Spec in the UK. These are the ones I bought. They make calipers with radius for huge discs as well as smaller ones.
Hi Spec Motorsport
Check out the
Monster 4 radial mount 300mm this is designed for a 300mm disk which is close enough to the 285mm jag disc that the radius will be right. They come in different widths and you will need the 28mm versions to fit the Jag discs. Probably a bit more expensive than a Wilwood but cheaper than an AP.
The Monster 4 radial mount is what I'm putting on the rear. They are a very nice piece of hardware. All their calipers are machined from billet rather than castings. They also hard anodise the caliper bores and the pistons for wear resistance.
I went over kill on the front and bought the largest calipers they make. The Mega Monster 6 (I know the names are pretty lame).
These are the Monster 4 330mm version
You can see the dust seals in this pic
Cheers