Any big shrub that is transplanted needs to be well watered at least once a week, unless there's a spell of frequent rain (not drizzle). This should be kept up throughout the summer after which it should have become established. Greenfly are a big pest of aphids and different to the types that attack apples, strawberries etc. Soapy water doesn't kill them. It knocks them off the bush. Cut back a few of the stems by half to an outward bud and see whether new shoots are produced as a result If so cut the rest of the bush back ny half.

The best insecticide I've come across is Permethrin (used to spray clothes against mosquitos). You can't buy it from garden centres any more but Amazon stock it in concentrated form. You need to dilute it with about five times its volume with water to spray safely on plants but it certainly gets rid of aphids, and other insect pests too. It also kills bees so if you ever use it don't spray it on flowers and they'll be fine.

Although its the wrong time of year it might be worth taking two or three cuttings. This works well in autumn, but I've never tried it at this time of year. Just cut off some shoots about 10 inches long, remove all the lower leaf buds and most of the leaves and just stick them in the ground somewhere. Done in Autumn these usually root over the winter. Put them out of strong sun though (haha, chance would be a fine thing)or they will just dry up - they probably will anyway but they certainly can't root if you don't try! Forsythia will root like this as I found out when I used the prunings for dwarf bean sticks.

thanks both... will try a bit of pruning.... had blackfly on it today... but i am not giving up!