I am searching for more details about the encounters between 235 Sqn Blenhiems and Do 17s on the 30 June 1940. This is what I have found so far.

AIR 28/838 ORB RAF Station Thorney Island
“Combat ‘Lab’ by 235 Squadron. 3 Aircraft
2 Dornier aircraft patrolling 2728. 2500 rounds fired. Enemy gunner silenced. 1 shot through exhaust ring. Dornier dived to sea level.
Combat ‘Lat’ by 235 Squadron. 3 Aircraft
1 Dornier Do 17 engaged. Difficulty experienced in making successful attack owing to insufficient speed of own aircraft.”

Maybe the Appendices have more to add but I have no copies.

Chris Goss has given me the following information from the CC Intsum and the unofficial 235 Sqn diary.
Intsum: B&T of 235 Sgn damaged Do 17 in KLWS 2728.
235 Sqn diary: Sgt Hobbs and Sgt Coggins patrolled off Guernsey.

According to Log book of air gunner Colin Chrystall (New Zealander in the RAF) he flew in Blenheim ‘B’ with Sgt Quelch as pilot. Up 1120 hrs. They escorted MV to Guernsey and then patrolled of Guernsey. Chased one and attacked another Do17 which was seriously damaged.

Thanks in advance,