Too risky. The car stays put until it's sorted.
I've been stung before doing exactly what you describe there.
Never heard of that before.
I've dropped plenty of cars off at night over the winter. Are the customers fooked ? Nope.
Any problems with the car doesn't matter how long the list then the bodyshop will sort out, pending it's their fault. But yes you will unfortunately get a bodyshop courtesy car as it's nothing to do with insurance.
Paint warranty is like 3-5 years at least.
If it was me and the finish date was before you went away, I'd pick it up have a quick 'glance' over, take it on the trip, do your business then if you come across any problems take it back once you get back. Yes, you might get a C1, but at least you don't have to drive a "dreaded diesel", in the lakes.
P.S IF you do take it back, please don't say there's stone chips in the front bumper, lolz.