I'm guessing well specced up these are going to be getting on for £40k, getting close the that 820 still for sale

Mmmm.
Looking at the specs and diagrams it seems that the extra 18ins in the 6XX vans hasn't been used to make the washroom any more user friendly, except possibly by making them deeper using some of the additional 4ins width. Though that might just mean a wider gangway.
They appear to be emulating a 565 by putting a larger fridge on the nearside between washroom and dinette. That presumably leaves a space in the kitchen which has been extended anyway by the extra length, though knowing Eriba it will be extra cupboards, nor used for an oven and grill.

One thing puzzles me on the 642. They've made the bed 6ft 6ins and 6ft 10ins long, when the 542 has 6ft 5ins already. There can't be many customers that need beds longer than 6ft 5ins. Surely that extra bed length space could have been used for something more useful.

looks more like Coleman's Mustard colour to me.

You could have mustard with nuggets. You could, I wouldn’t can’t abide the stuff 😁

Purtle would be good.