The website is not up to date, even if here I believe it is true.
Galland's victory and death were 5 hours apart and related to two different actions.
Around noon, AFAIK, only low-level raiders operated over NW Europe: Bostons of 2 Group flying cloud-cover raids and Spitfires flying Rhubards in small groups. One Boston of 107 Sqn was shot down, reportedly by a Fw 190 (story is in the book "The Reich Intruders" by Martin Bowman) and two Spitfires of 340 Sqn were lost, reportedly to Flak. But I found a report (here:
http://www.francaislibres.net/liste/...hp?index=73785) that the four Spitfires dispatched by 340 Sqn split into two pairs, and one pair disappeared after going towards the railway between Calais and Saint-Omer. They were SUPPOSED to have been shot down by Flak. One pilot is still missing but the other was captured and survived, so maybe he let a report telling what shot down him.
On the German side, two claims are known for this time period: a Spitfire at 1250 hrs by Obfw. Paul Kirstein of 2./JG 26 5 km westlich Etaples (his 3rd kill) and a Boston or a Spitfire at 1310 hrs by Lt. Paul Galland of 8./JG 26 at 1310 hrs 13.10 7 km southeast Dixmuiden (his 17th kill).
Kirstein's kill could have been the Spitfire IX BS535 of 340 Sqn flown by Lt Claude Helies, who is still missing and could have been shot down over the sea.
Galland's claim is over Belgium and the Boston crashed here, while both 340 Sqn losses are supposed to have been in or off France.
Mr Prien being a user of this forum may comment on why a Spitfire has been set in the JFV book for this claim.
As for who shot down Galland, his wingman, Fw. Johann Edmann of 8./JG 26, claimed to have shot down it just after the Spitfire pilot shot down Galland. Only two Spitfire pilots were shot down in this battle, Flg Off Gibbs of 91 Sqn (Spitfire Vb AD548) who was killed and Flg Off Galway of 453 Sqn (Spitfive Vb EN786) who was rescued by the Air Rescue Service in the Channel. As Galway did not claim any victory, if we believe Edmann, Gibbs should be the one who get Galland.
But Edmann's was one of 6 victories claimed by German pilots during this battle, for only two RAF losses, so actually the British pilot could have survived. Overclaiming was also on the British side, with exactly the same ratio, 6 Fw 190 claimed (five by 91 Sqn, one by 122) for two German losses.
Things who could check further:
1) were there ground witnesses for the downing of the Boston that may confirm it was shot down by Fw 190s ? Chorley says in his BCL book that details can be found in the Belgian book "Vermist Boven Vlaanderen", it may contain such witnesses reports.
2) does the surviving 340 Sqn pilot, Capitaine Chauvin, write a report describing how he was shot down ?
3) you can check RAF combat reports for this day to see if one describes an action comparable to what Caldwell describes in his book (ie getting out of cloud, shooting down a Fw 190, being attacked by the wingman).
Best regards