Well after lunch, and the recent offer of a cheap new in box Primus Fridge I thought i'd look into it. I wanted minimal fuss on the upgrade
(wishful thinking its called) and to fit in my rear storage without too much issue... I have plenty of room long ways and some on top, but from memory, width will be the deal killer.
After some googling (lots from kulkyne kampers site) interesting size differences and weights on the ones I've looked at which means new slide, and possibly rebuilding the rear storage unit too
(which fits it neatly into the TFH basket). Will have to measure up the storage tonight. I know the slide I have only just fits the 40 on it now
So looks like no matter what I upgrade to, none will fit in where the Engel 40 was