SEAT Alhambra (2014) spare wheel

I have a SEAT Alhambra (2014) which does not come with a spare wheel. I want to buy a cheap spare wheel (2nd hand maybe), that I can keep in my garage for emergencies but I have no clue about these things. All I know its a bigger wheel than by Skoda, can I find what my size of wheel is and get a generic spare wheel for it? or can I use a same size wheel from a different brand car (2nd hand)? I think my wheel is 16 inch, will any 16 inch wheel work on it?
I Tried googling this but can’t straight answer ( most result are websites selling new wheels)

If it makes any difference, it a UK car