I have put some on my '00 Rev3 with no problems. They were available as a Beta part with the new clamps for '98 Beta Techno's, and are only available in red. I suspect that they are Domino handlebars. The total cost was NZ$260 including the clamps, so should in theory be available from the UK Beta distributor for less than 100 pounds.
Bloody good handlebars anyway - I haven't even bent them yet, and I do crash fairly frequently......