You will be able to get a spray from Tesco's or Sainsbury's in the garden section or from any garden centre. There are lots of different brands. Everyone seems to be plagued with them this year.
Cropsaver or any other systemic spray.
Plants and flowers will not be effected
but please spray in the evening when the Bees have done their days work.
Me again sorry to contradict previous answers, Washing up liquid is next to useless, systemic spray is absorbed by the plant and when the blighters feed off the sap "Good night Nurse"
Sorry to contradict you lindylou but washing liquid washes off the protective coating on greenfly and thus kills them. Scientific fact. Perhaps you didn`t use a strong enough solution.