19 inch -v- 18 inch wheels

Hello I'm new to L Zone. I have bought a 2014 Freelander Metropolis. I want to use it as a bit of a workhorse and in particular take to France for the ski season. It has 19 inch wheels 235/55/R19 [and no spare which is odd for a 4 x 4?]. I am thinking about buying 18 inch wheels off Ebay and putting winter / chunky tyres on. That way I simply change the wheels over rather than swapping tyres and risking the alloy rims.
My first question is - assuming that all the wheels match [i.e All 18 inch / 17 inch etc] will it do any damage on a car currently set up for 19 inch wheels?
Secondly, there is a 19 inch spare on ebay - different alloy design - but would it fit as a spare? I don't like the idea of tyre repair kits. [ Major tyre blow out in France leading to big accident - nightmare - don't ask!!].
Thanks in advance for your comments
Lawrie

Welcome. Questions are better placed in the relevant forum, rather than here. Good luck

Allegedly that extra inch makes all the difference, but I don't believe a word of it!!

You need to tell the car your running different sized wheels as the speedo will be wrong, also spare wheel is an optional extra when ordering from new, otherwise you'll have the tyre foam, which isnt all that great imo