I pass my MOT with the wrong size spare in the boot.. But i guess thats not something they check

This is all a bit off because where you think 5mm is nothing.
If I use the calculator it says my current width is 592 with 205/40/17
But my spare is 632 with a 205 55 16
6% difference. And its says there should be 2.5% difference max!
Ive got a spare 205/40/17 tyre so i just need a 17" wheel with 5x100
