Mathieu,
The Fokker D.XXI would have been "229" with pilot Sgt.Vl J. (Koos) Roos that crashed at Nieuwkoop.
The nimh.nl website gives some Bf-110s lost/damaged over Zuid-Holland (Waddinxveen, Leiden-Gouda, Reeuwijkse Plassen....) on 11 May 1940. Unit would have been ZG 1.
In Peter Cornwell's book "The Battle of France Then and Now" however no loss of a Bf-110 is described that fits the picture. The two Bf-110 losses (one damaged, one crashed) over Holland are attributed to flak during an escort mission to the Gorinchem area. These belonged to 3./ZG 1.
Roos sometimes is said to have flown in "225", but this one apparently was lost on 10 May 1940 with Sgt. Looijen at Ouderkerk a/d IJssel.
The exploits of Sgt.Roos and the thrown away cockpit are well-described, but your question what Luftwaffe losses match the story is indeed worth a try to look into!
Perhaps contact the NIMH in Den Haag and ask what more info the records T513, 514, 515 and/or 516 hold for you on the
Verliesregister 1939-1945?
See
http://www.nimh.nl/nl/images/1940%20sec_tcm5-7281.pdf
Regards,
Leendert