There are two issues with these claims.
First, all claims of ObLt Steinhoff are un-timed, which makes it difficult to verify the details. But this is my thinking:
- the first claim of Steinhoff (his 3rd) seems to be clustered acc Prien with the two claims of Ofw Förster of the same unit, both being Fokker G-1's. This would date the claim as early morning May 10. At that time there were no Blenheims active over western Holland yet. But aircraft recognition was notoriously bad on both sides, so there is a high likelihood that the a/c claimed was not a Blenheim. The closest in terms of appearance over this theatre is then a Fokker T5, but then there are no unaccounted Fokker T5's at that time.
Alternatively, if there is no match with the two claims of Förstner, it could be a Blenheim of No. 40 Sqn in the afternoon around 4.30-4.50 p.m. BST. At the same time these a/c also seem to be claimed by 2./ZG1.
- the second claim at Duesseldorf seems a bit easier, and also Peter Cornwell followed this explanation. In the morning Blenheim L1405 of No. 18 Sqn was sent out to reconnoitre the Maas bridges and German crossings, and was shot down somewhere along the Dutch-German border. So from a location perspective this seems to match. Time around 09.00 BST.
The last topic is then the unit of ObLt Steinhoff. In the Tony Wood list, referring to Prien it says 11.(N)/JG26. First, this should be 11.(N)/JG2, probably a typo. But then according most sources only 10. and 12. Staffel were based on the western front in Hopsten, while 11. Staffel was at this time in Trondheim, Norway. So assuming that Steinhoff claims are correct he should be from any of the other two Staffeln. Can someone confirm? Alternatively, Steinhoff was indeed in 11., but then his claims should be over Norway.
So still some open questions.
Regards, Pieter