MS90 and a SP30 on licence from last March which I new nothing about

[Man in the middle]

1 hour ago, Dawn33 said:

I work as a driver so they aren’t my cars

What aren't your cars? There has been no mention of any cars up to now.

 

As above, it is imperative you perform a Statutory Declaration (SD) asap to get the convictions set aside. If for no other reason, one more conviction which attracts points will see you face a "totting up" ban. What happens after that largely depends on the circumstances behind each of the convictions. If they stem from the same incident it is most unlikely you would have been convicted of speeding as they have no evidence you were driving, but stranger things have happened.

 

You need to find out which court convicted you so that you can perform the SD.  

[Man in the middle]

1 hour ago, Manxman in exile said:

although the 3rd March speeding offence will now have been over 6 months ago, I assume it won't have timed out

 

Correct. Although the SD sets aside the conviction(s) it does not nullify the prosecution. The date it was begun remains intact.