As far as I can tell when AM failed to pay the €1.8m to Saints on time as per the loan agreement, Toby's registration is retained by Saints as soon as they pay the transfer fee agreed last summer.
In other words, Toby's registration was not theirs to sell - to Spurs or anyone else.
I can't see Saints letting this go, as far as I can see they've got AM over a barrel.
IMO