According to my book Snoop : little or no pruning required -merely remove damaged branches , not much help I'm afraid ,give it time it may well spread out now it has more room , good luck with whatever you decide ....

You can cut it back - but now is not the time to do it, unfortunately, best done either in late autumn, in winter or in mid spring. If it was the beginning of June, I'd have said do it now, but obviously, its not. Which means you're stuck looking at it like this until late autumn at the earliest...