Hauser and Alfred,
Many thanks indeed. Hauser, I have looked at the carts, but my garage is so tiny there are bruised cat marks all over the walls where swinging tests failed. I don't have room even to stow the cart without fear of damaging it's (very new) respray.
I like that German system, Alfred. Typically ingenious - my wife approved and made some vorsprung durch type-comment before wandering off. Sadly, I don't have the room. (I would post a shot of my garage, but having seen the likes of some - Mr Lews for one - I fear I might lower the overall tone of the website).
So, I fear I must design and build from scratch.
Paddy - I would always keep my top. I drove most recently to S France from N Germany; 2 days at 65mph (Arrhhhghhghggh!!!!!) Anyway, the reduced road noise and added security made a vast difference; we just ditched the top when we got there. Alas I don't have the roof with a sunroof as shown in Alfred's photo, but here's one of my mutts on the trip with us, which I like far more (and the passenger today came second in Best Btich over 7 at the Chiswick House Dog Show - sadly it's gone to her head somewhat - bit of a prima dogga):
JH