After a bit more research by myself and Mr Sinistar, we belive that the actual key is indeed a Weiser as per Young Paddy's observations above.
The Weiser Key
Appears to match the film screenshot. It is hard to tell whether the film screenshot key has the curves edge of the stock shot I posted above or not but all other dimensions seem to match including the hole for the key ring and the shape to the top of the key. The keys come as either 'brass' or steel in colour and I have located somewhere that supplies blanks.
Looking at the screenshot, I believe can also identify to some extent the door knob and door furniture, or at least the modern equivalent.
Again, this could be any brand of doorknob but if the keys match then I would expect the doorknob to be of a same/similar brand.
The 'Beverley' Polished brass effect door knob seems to match the best.
The screenshot also shows a double door for the shot with a blank door knob that is of the same design just without the keyhole.
The same company also utilise fixtures for the double doors. These no longer appear to be square but have corners removed, possibly for cost.
Rebate set for double doors with doorknobs
Have a look and let me see what you think.
I have also sourced a supplied for the blanks of the key, but again this may just be for display as I doubt the key will match many other locks out there.
I'm off to get more fobs made!