I have, however found a (probably temporary) solution. I was at a classic car show with my Grandad, and there was a stall selling all sorts of bits of rubber, trim, heat shielding etc etc, and he has some plastic chrome look (and it is pretty good) gutter trim (I think it is for minis) for £3 a metre. Bought 4m of it from him and have tried it on the rocco - see what you think in the piccies below.
It isn't 'right' it is only an upturned U profile, so doesnt wrap around the gutter fully like the VAG trim does, and obviously you just have to cut it to size, so the ends aren't finished in the same way as the proper trim, but it tidies it up quite well until I can find a proper passenger side one in good nick (plus £12 for the whole lot to do both sides I figure you cant complain!). It has it's own adhesive on the inside, and seems to stick quite well, including a couple of quite long journeys at 'autobahn' type speeds, it hasnt yet tried to escape from the roof!
Excuse the crappy paintwork - it is temporary while I repair bodywork, but you will get the idea:


The company is called Autohose - they have no website, but details are below if you want to get some - make sure you ask for the high gloss one, as they had some more matt finish too.
Autohose, 9 Bagnall Road, Milton, Stoke-on-Trent, Staffs ST2 7AY
Phone - 01782 542486
Mob - 07931 728956
Fax - 01782 252219
Hope it's of help to someone, as I know that even with my temporary paintjob, having no trim on the gutters was driving me up the wall!