The third vaccination needs to be between 150 and 215 days after the second one if you want to compete under riding club rules at any point.
Make sure you don't have it too early or you'll have to start again!
I waited until another horse on our yard had a vets visit and shared the appointment.
Excellent thankyou, i've just checked and 2nd jab was done on the 27th july so i think that should give me a couple more weeks to get the 3rd booked (if my math was correct!!)