[Laurent Rizzotti]

Thanks to your replies,

Well the case darkens...

I summarize:
_ in the Blitz T&N, "two Junkers Ju 88s of II./KG 30 and one from 5./KG 1 were lost on June 7" (not in England, so outside the scope of the book for details)
_ in the Osprey book about 43 Sqn, a claim by Dalton-Morgan for one of the losses of KG 30 was "on June 8th". I assume that it was the night of 7-8, and it was confirmed by the Fighter Command activity file by Tony Wood, that showed the claim as 0010 hrs on the 8th.
_ but the book "The turning point", in which I did not find the KG 30 losses, had them on the night of 8-9 June, which I did not check. Thanks Jim for pointing them.
_ by rechecking Tony Wood's file, the claim by Dalton is shown on the 8th at 0010 hrs but during the night of 8-9 June, so something is wrong here.
_ Jim shows both losses on 7 June, and I guess this date is coming from the Luftwaffe loss list (Gen.Qu.6.Abt)

So in the end, I guess at least one of the losses, the one shot down by Dalton-Morgan, was effectively 10 minutes after midnight on the 8th, and so started on the 7th and was logged on this date by the Luftwaffe.

For the other loss, Foreman says the Cottesmore downed it over the Loch Ewe on the night of 8-9 June. As Rainer says, the Cottesmore was escorting a convoy in the Channel on the night of 6-7 June.

By checking the Admiralty diaries, on 7 June, the boom carrier Ethiopian was damaged by two near misses at Aultbea, in the Loch Ewe, at 0957 hrs.

On 8 June, according to the Admiralty War Diary, "a second attack was made between 0100 and 0200 this morning upon Loch Ewe by 3 to 5 A/C apparently acting in conjunction with a raid in the Minches. One A/C was hit and another is claimed as shot down. No mines are reported to have been dropped, and no damage was done by the bombs.
"AM 8th One aeroplane was definitely hit but not seen to crash and inflated dinghy has been recovered out at sea belonging to a Dornier 18. GIv 854. Search is being made for crew over a large area."
"Air attacks were made on Loch Ewe on mornings of 7th and 8th between 0100 and 0200 first attack was spasmodic and probably by passing aircraft. Second attack was planed and resolutely carried out. Slight damage by near miss on Ethiopian during 1st attack. No damage second attack one slight casualty from bomb splinter on Merchant Seaman. One plane claimed brought down and another definitely damaged. Confirmation of plane brought down not definite. Plane seen going out to sea in difficulties. Rubber dinghy fully inflated has been recovered. Search is being made."

So it seems that the second KG 30 loss was during the attack on Loch Ewe during the early hours of the 8th. I wonder what anabled the British to identify the recovered dinghy as coming from a Do 18, but it should have carried German markings at least.