Wife likes a house where access is up a narrow 17% hill, caravan laden 1350 car limit all variants with automatic transmission 1800 it is a Jaguar XE. So there is some leeway.
We have the 163 PS version of the diesel engine same engine also has a 180 PS version just different engine mapping, with there being no difference in maximum tow weight I would assume power is not the limiting factor.
In the main the Jaguar XE will not be used for towing, the Kia Sorento is main tow car, however we had a tow bar fitted to the Jag as Kia is getting old so in 5 years time we may be forced to get rid of it.
So if the Jag will not tow up the hill then we have to consider if the move is really on.
I'd be more worried when bad weather comes. While a 4wd is great up hill, it will still slide down a steep icy incline without a caravan on the back. Living in your neck of the woods I suspect this a regular occurrence during winter.
I am not familiar with the Jaguar but if it is front wheel drive you may find the front wheels spin going uphills in the wet on such a steep hill and the caravan weight at the back.
Ignoring friction and rolling resistance etc, the actual pull on your hill is 1350 * 0.17 = 229.5kg.
A 1 in 8 hill would be 1350/8 = 169kg.
That's quite a big difference.
We live up a 1 in 8 and I tow ours up. 1150kg MTPLM 1300kg max tow. I stop at the bottom and set 1st gear then go for it. It is an easy climb. If I had to stop I would be more worried.
I would use the Sorento then sell both when the time is right and get another sorento or similar. Although they say a dog is for life not just for Christmas I assume it must be the same for a big cat too
------------- its our imperfections that makes us perfect
My understanding is that the towing limits of cars are set based on the weight that it can physically move from a standing start on a 12% hill (1 in 8). Given that the weight you're pulling is almost half a tonne less than that I would have thought that you'd be ok. As has been suggested, snow or ice might make it impossible but are you really likely to be towing in these conditions?
You don't say how far away the house is from where you live now, but if it's a serious contender why not just take the caravan there and see how easy it is to tow it up the hill? I'm sure the vendors would understand.
------------- "Don't wait for the perfect moment. Take the moment and make it perfect."