Hi both my wife and myself own a T cross.
She has the SEL and the dealer fitted a full size 16 inch spare with foam insert for the jack and other bits.
If you quote your chassis number to VW customer services they will point you to your local parts dept who should be able to order this.
I could not get any info out of customer services about availability of a space saver other than through factory order on a new car.
I h just bought a pre reg Se so I decided to buy a 17inch from the tyremen in Hull. It is an alloy space saver and comes with a nicely packaged jack, a chrome steel wheel brace
an a bag for the wheel you have removed.
I agree a 17inch full size will fit, however you need to source an alloy wheel with a profile to match the car wheels and fit it with a tyre that matches the profile of those on the
car and is ideally the same make, plus a jack and wheel brace. That is the only real way to leave the spare on for long periods such as when away in the back of beyond.
The problem with the VW 16 inch spare when fitted to the front, is that it has a different rolling radius. This means that the diff drives constantly and that does not do the car any good.
It is the diffent rolling radius that forces the 16inch full size to be classified as temporary and which invokes the speed restrictions.
Space savers should really only be fitted to the non driven wheels so a front puncture means putting the space saver on the back and the full sized back wheel on the front.
On cars with 18 inch rims you only have a space saver option.
I had to source my own full size spare and matching tyre for a Skoda SEL I owned a few years ago so I was never stuck anywhere.
Hope this helps
Regards Chris