KB, your fuel consumption sounds about right, always assuming that you were of course in slow moving traffic on the A50 and not risking the wrath of the boys in blue!
DUK won't tell me if they identified this as a design/installation fault, only that replacement of console should/will resolve problem, They also suggest that, "any others who are experiencing similar difficulties should contact their local dealer".
As for availability I'm reliably informed that parts should be available within 2-5days of Dealer ordering. Yeah right, that'll be a first for Ducat!
I'll keep you updated!