My London daughter is looking to plant a short length of hedging, 3 to 6 metres and is looking for something that would only need trimming once a year and ideally have some edible interest for herself or possibly wildlife. It is quite sunny with, I suspect, poor soil.
A selection of red, black & white currants.
Chaenomeles Japonica - Japanese flowering quince. Early flowering, loved by bees, spiny to deter unwanted visitors, fruits make lovely quince jelly.
mixed currants and possibly gooseberries as well would be good. The birds would likely take all the red currants but gooseberries and blackcurrants could likely be harvested.