For any MOT reapirs done by failing garage it has to be left there an then.
It is simple you pay lots to get it fixed, or you pay lots in increased premiums if you tell your insurer, the other party are likely to inform the police/insurance co anyway.
This all goes on a database.
Some might disagree about the NOT A DICK part, myself included.
You take the risk, you can lose and you suffer the consequences as here.

tabetha