When I'm back in the country at the weekend I will photograph the spare wheel I have and post it here - it is a Porsche one and I know you are looking for an alternative, but I couldnt find one that was going to work having looked everywhere for quite a while. I got the spare wheel because I seem to be magnetic to all things sharp and pointy on the road. They are not cheap new, do use your PCGB discount if you have to buy it from Porsche.
I agree with tscaptain, you may have a problem putting it anywhere because it is bigger than you imagine and I think the boot space is compromised in the turbo because of the 4wd system. I have a Carrera and it fits fine, but takes c. 40% of the space up (you also need a very large bag so there's something to put the real wheel in if the worst happens).
I did read about someone fitting a long threaded rod to mount the wheel in the boot, but that rod was directly in front of the petrol tank which seems like a risky place, I have two luggage straps diagonally fitted behind the panel with the puncture gunk etc in it and it holds the spare steady enough.
As for the jack, I bought a second hand Porsche one with the polystyrene insert to sit in the spare wheel, its aluminium and super light and does lift the car (you can also buy a hockey puck to protect the car jack point, though how you're supposed to get that and the jack under the car at the same time is a different story unless you drive onto something to elevate the sill. I also carry a long torque wrench to loosen the bolts as the brace I had was useless and it also ensures I tighten the bolts up properly.
Hope this helps