when to cut gorse hedging!

I have a fairly large area of my boundary that i planted with evergreen gorse, it has flowered, its in good nick and about 5ft high. last year i trimmed it back and it made it very neat and formal.when is the best time to do so? i want it to get to a max of 7ft but dont want it to get woody and lankey! all advice appreciated. Thanks ,dinky