As Craig correctly says, you’d be surprised just how little difference there can be between the lengths of the longer models of single axle and double axle offerings from the various manufacturers. As an example, take a look at the tech. Specs of the sprite models by Swift which you can find
here .
Although these are of the Sprite models, the models higher up the swift range are the same dimensions as they are the same layouts albeit with different furnishings and different general specification.
You can see that the single axle 6TD layout is only 440mm shorter internally than Swifts twin axle Quattro models, although the Quattro, depending on layout is at least around 100KG heavier which is a significant amount of extra weight. I’m certainly not suggesting that you shouldn’t go for a twin axle, as there are of course obvious benefits associated with these models, not least stability, or that the 6TD is the layout for you, but I wouldn’t be so quick to dismiss all single axle vans with the preconceived idea that twin axle models are much longer.
Whilst there are of course advantages of a twin axle, on the flip side, there are also other things to consider, such as the additional weight, the requirement for a twin axle motor mover and possibly double wheel locks.
Ic.
Edit: Then again, myself and Craig probably are somewhat biased as we love our vans, which are both based on the single axle 6TD layout. Loads of space and sleeping options for a young (ish!) family of 4 plus guests ...