Hmm, I thought they could be aerobatted two up. If they can't then there's no point in having one. I'll have to dig out the weights allowed.
They seem to be a mixed bag regarding certification; there's at least one on an EASA ARC on the German reg but based in the UK and there's also at least one with UK reg on an LAA Permit. Again, for me an LAA Permit is the way to go as I have a CAA "Licence for life" and have no intention (at the moment) of converting it to an EASA licence.