Little update for you guys,
Car is booked in for Tuesday next week, in the meantime I did a little experiment earlier today. I placed a new TPMS sensor on the floor by the rear tyre that currently has a dead TPMS (bought via the above link) I then did a TPMS relearn on the car dash, I had horn pip on every corner. Obviously confirming the TPMS is in working order and the car / relearn tool picked it up straight away.