Myzus ligustri sometimes called the Privet Aphid is pale yellow or greenish-yellow.  The aphids produce a pseudo-gall by causing the leaves of Garden Privet or Wild Privet distorting the leaves, causing one or both margins to roll downwards. There is often some discolouration of the affected leaves which may have patches of yellow.  For more details, see the 'Further Information' link below.

Please provide images of the pseudo-gall and the aphids if present. Please also state the host plant.  Privet leaves may be rolled in this way for other reasons and it is best to make sure that there are signs of aphid activity within the leaf roll before recording.

Found on Garden Privet and Wild Privet.  

April to November. (Sexual forms are produced in November).

Myzus ligustri does not host alternate but spends its entire life cycle on Privet.

Fairly widespread in England, but not particularly common, although it may become numerous where it is found.

Rarely recorded in Leicestershire and Rutland.

https://influentialpoints.com/Gallery/Myzus_ligustri_Privet_aphid.htm