Soldato
Have to admit I completely overlooked the whole L plate / M road thing also. 
If it's insurance you are worried about you will probably find a non-sports 500/600s (which will still go like like a rocket) will be cheaper to insure than a sports 125, especially if you are riding on a full license rather than CBT (which is out of the question now anyway).
I started riding when I was in my early 20s and TPFT (no NCB) on a GSXR600 was £600.
If it's insurance you are worried about you will probably find a non-sports 500/600s (which will still go like like a rocket) will be cheaper to insure than a sports 125, especially if you are riding on a full license rather than CBT (which is out of the question now anyway).
I started riding when I was in my early 20s and TPFT (no NCB) on a GSXR600 was £600.