Best Fittings have just sent me a new filler valve that actually replaces the original screw type male filler connector.

Basically Richard at Best Fittings has bonded a 'Daystate' type quick fill valve to a Falcon OE brass air cylinder end which means you can replace the screw type end for a more convenient quick fill.

He even supplies a dust cap for the valve (I'm going to turn down a Daystate dust cap to the same diameter as the falcon cylinder). All in all it's about £50 which is reasonable as it's the same price approx as his Falcon screw on quick fill adaptor which adds weight and length to a rig (pistol or rifle). If you have the Best Fittings kit for filling up your guns you should also have the required female part to clip to the probe saving money.

It's really worked for me as I have a Falcon pistol but didn't like the screw on connector so looked at Best fittings who do an adaptor but added length and weight to the pistol which didn't suit due to a permanent shoulder injury. This way, the pistol is actually lighter (by a few gramms) and no longer than before.
Top bloke for sorting this for me.
He'll be doing this for anyone who wants one using genuine Falcon parts. If anyone does call him for one of these be advised that he's just gone for a well earned break for two weeks until mid September. I guess you can leave him a message through his web page.