Hi,
I picked up a brand new one from Cheshire gun rooms last year and pretty sure Falcon (NSP Engineering) still have some left - ask to speak to Chris as he was the Falcon guy there before the operation was wound up. Also try the Falcon forum who are a pretty friendly bunch and might be able to help. Feel a bit guilty as I don't use mine and only wanted for 'completion' (missing bits of guns drives me potty )
Good luck
Chris
Falcon Raptor (FN12) Lighthunter - Walnut FX Cutlas - EB XVI - HW35 'Karbine' - BSA Airsporter MK4 - Webley Mk III - Relum Tornado - FWB Sport 127 Deluxe - Crosman 1322 custom - Sussex Armoury Jackal - BSA Superstar - Logun Eagle (All .22) and HW80 in .25