Thanks Moggy and Viscount. I don’t think they were Extras, but I could be wrong (it has been known!). I’m wondering if they might have been on their way to East Fortune where there was a display today. The two non-yellow aircraft may have been Van’s RV8s but my recognition of single engined display aircraft is not very good. The yellow aircraft had higher aspect ratio wings than the other pair and could have been Fireflies.