Are you sure of the date ?
Tony Wood's claim list includes a Bruchunterlagen list for this day, not showing your loss.
The only Mustang listed is at 14h16 near Terwolde, and was the 4th FG aircraft that spun in clouds for unknown reason while escorting bombers returning from raiding Hamm.
It was the only USAAF P-51 lost over German-held territory this day (4 crashed in Allied territory). No RAF Mustang was lost in operations this day AFAIK.
The only afternoon loss of the RAF is probably your aircraft: the Typhoon Ib MN379 of 439 Sqn was hit by Flak during a raid near Issum and force-landed between the lises NE of Geldern. Pilot was rescued by US troops and then a German patrol came and destroyed the crashed fighter. Time of this mission was from 14h10 to 15h00 (Allied time).
For more details see the 439 Sqn ORB available on-line:
http://www.rcaf.com/439squadron/275.htm