further research shows the Bf110 was on a mission to Portland when it was shot down at 17:40. (The Blitz, now and then). looking at a map it seems to have been taking a scenic route and maybe was overflying Southampton as well…
The Bf110 was 5F+CM from 4 (F) Aufkl 14 at Cherbourg; the He111 was possibly G1+GN from KG55
Both involved in a raid on the Supermarine works at Woolston near Southampton
Many thanks guys. It seems it is usual to quote serials without codes in all the references I have found; is there a document anywhere that matches up both of them?