Joe--
The 414 Sqn late-war livery was very basic in any case; in essence it's similar to two RCAF Merlin Spits that have been restored in recent years, "Grace T9" PV202 and XVIe SL721. Dark green/ocean grey/light grey finish, no Sky fighter band (though the paint over the band would be fresher and thus perhaps a darker colour), black spinner, C1 roundels in all six positions, black serial. Only the individual code letter (in Sky) would appear, below the cockpit, just ahead of the camera port. You could cheat and assume the code letters lined up with the AirMin serials...with NH896 being "B", that would make NH904 "J" (an absurd assumption of course, but you can always change the codes later! Or hey, just use decal letters).
Or you could just paint NH904 overall bright red with an "RCN Sea Fury" star spinner. Can't explain why...I just have this odd feeling it would look nice...
Cheers
Steve