I would double check with the vet not the secratary as she may have just got confused.
I also am not aware of any rabies vaccine been administered more that once.
The normal protocol is id chip, vaccinate, blood test 21 days later (if pet coming back to uk) and issue passport (uk issue passport if acceptable titre level reached, if not repeat vaccine and re blood test).
Boosters are normally between 2 and 3 years depending on type of vaccine used.