Andy, That's not as dirty as your Mk2 after me and Shelvey used it for Autotest in the sand and gravel quarry at the weekend. 
I assume you were pushing it round then Simon???
As for the Mk6, the wife was giving me some right grief about it at the weekend and, at first I wasn't going to wash it as I don't finish work til the 21st so it'll be just as bad by then. But in the end I relented and washed it yesterday. I think I'll treat it to a proper clay and wax while I'm off.
Good job it wasn't the white one I was originally going to buy - now that would have been filth!!!