Yup.
Just had it checked by the guys at my local store. Seems it is in fact a Classic Army M249 para (albeit rather old). Still works, shoots fine. Needs a new trigger switch (apparently they all do that). The guy I bought it from was having some custom paint done by me on his Vinci shotgun which I was charging him £50 so it's actually only cost me £25 and some paint and time. Needs a clean up and minor tweaking (new switch, new hop rubber kinda stuff) but yeah, quite chuffed