My spare wheel story went like this. After I'd ordered my car, I did a bit of research about the "standard" foam solution, and discovered that there are quite a lot of situations where you can't use it. As I didn't fancy having to be recovered if I got a puncture, I told the dealer that I wanted to buy the collapsible spare wheel (this was well before delivery). they came back and told me two things:
1) It would cost me a huge and outrageous amount of money (can't remember exact amount, but a lot)
2) They didn't know where I'd put it, because my car had a subwoofer where it would normally go.
So, I had a fairly strongly worded discussion about the cost, and they eventually agreed to supply it for the price listed as an option ordered at the same time as the car order, ?100 or so. They were still saying they didn't know where I'd put it.
So, the spare wheel arrived about a week after I took delivery of the car, I opened the boot, took the subwoofer out, dropped the collapsible spare in it's place, and then dropped the subwoofer inside the spare wheel, which is where it's supposed to go. You have to unclip one connector and unscrew the large woofer/wheel plastic retention bolt, that's all there is to it. Five minutes, if that.
Hope that helps,