Average fuel range on C class estate s205 220d

[DSM10000]

If the OP is getting just under 300 miles in city use, I expect he’d be seeing 400+ on longer trips anyway.

Not stopping for 300 miles in city driving would mean most people living in their car for a fortnight

Forget the larger tank, you’d want a built in facility…

My Series 2 LR had enough holes in the floor for alternative use