From quite a lot of looking around the net, looking at lots and lots of photos I have decided it's definitely a Mills machine, however it doesn't match any I have found through my searches.
The main casing matches the operator bell, however the window in the middle looks like the one found on the Mills poinsettia machine.
I'm assuming by the hand written scorecard not the regular rectangular operator bell type that it's some sort of aftermarket modification rather than a factory version.
Also the colour, would it originally have been polished and decorated or did they do more plain colour scheme versions for different markets?
I know nothing about it other than it has been sat in a summerhouse my entire life ( 40 odd years ) and probably several decades before that!
Many thanks to anyone who can provide any information on it.