Could be woolly aphid or if the blobs are like froth then Cuckoo spit. Either way wipe them off with a soapy brush.

Cuckoo spit? Is that another name for spittle bugs, Owdboggy?

Possibly! They are aphid like sap suckers which protect themselves from dehydration and predation with a covering of froth.

That's what they are then! I've got to remember that, though we don't have cuckoos here--except the odd assortment in the local park. ; )

Called that because the insect appears at about the same time as the cuckoo arrives from Africa.

Ah! Thank you!