Hello! I would do some pruning if you haven't already done so. Using secateurs prune each branch back by about a third, cutting at a leaf joint, so that you don't get die back. Don't use shears as you will cut into leaves. Pruning can also be done in the autumn taking just a few inches from the branches. You should soon find that the branches will start to bush. Give a good feed of a general fertiliser now and at the end of July. Make sure that the soil does not dry out until the hedge is established. Hope this is of help.