From RFC Communique No 107:
"Capt J T B McCudden, 56 Squadron, dived with his formation at EA and selected one which he destroyed. The wings were seen to fall off this EA before it reached the ground, and the pilot fell out at about 8,000 feet. Lt L M Barlow dived at another which was seen to crash, while Capt G H Bowman and Lt R T C Hoidge each destroyed an EA. Lt A P F Rhys Davids shot one down out of control, and it has since been reported by French infantry to have crashed."
The Communique is somewhat misleading as it describes two separate events; McCudden's claim was timed at 08:00 over Houthulst Forest, Rhys Davids' at 08:15 near Comines and Barlow's at 08:15 south of Houthulst Forest. The "each destroyed" claimed for Hoidge and Bowman was actually shared between them at 17:20 east of Westroosebeke (a good fit for Wisseman's loss).
I have seen McCudden's victory ascribed to the loss of Ltn Herbert (or Gunther?) Pastor of Jasta 29 who was killed on this date; the location in
Casualties of the German Air Service is Veldhoek - just south west of Houthulst - so seems possible.
Graeme