That farce can go on for ages... I remember sitting at the hold once in an aeroplane that was costing me £160/hr while 5 or 6 other aircraft were flying circuits. I watched one Tomahawk do 5 touch and goes while I was waiting. It would have cost me £50 had the club not given me a discount.
It's damned annoying, especially when you're not planning to stay in the circuit and when you're flying a powerful aeroplane which doesn't need much of a gap in the traffic to get away.
Having said that, my understanding was that the FISO controlled everything on the ground up to and including the hold - i.e. you need authorisation to pass the hold and enter the runway.