FINALLY - found a replacement towcar :-)
I think it had got to the point where if I showed my partner one more car on Autotrader, my laptop would have been wedged into a very uncomfortable place, so this week I finally bought myself a replacement towcar, 
On a more serious note, all this looking at cars, reading reviews and owners feedback, does make me wonder if many diesel cars in the future will be suitable for towing, with much smaller eco focused engines, lighter vehicle weight and ever more complex
emissions equipment making them less suitable for towing use.
This time I am fortunate as bought a very low mileage 4x4 that has a full sized spare wheel and free of both that blasted DPF and the annoying stop start technology, (which is fine till the car won't restart in a right hand filter lane etc). I do wonder
in future years whether there will be suitable vehicles out there, whether those smaller engined eco engines will have torque and power curves that will still be capable of pulling heavy caravans, as the caravan manufacturers seem to be doing very little to
reduce the weight of their offerings.
Makes you wonder about the long term implications for caravanning in general sometimes. 