Anyway, for now, at least I'm starting to snatch the odd moment here and there. Not much. But it's a start! And I'm content to lower my build standards just to get stuff done. Plus these old Airfix kits are, without meaning to be rude to such long-serving old-timers, more at the Sow's Ear rather than Silk Purse end of the model making spectrum.
Not sure when I first drafted this post, but this evening - at least one day, poss more, after posting the above - I've now assembled the gun. So Airfix Vintage kit #2 is built. If I have any more, I'll build them, and then set to painting and adding decals. Might do some minimal additional detailing. And I have to decide about whether or not to use the rather clunky figures. But I am gradually getting back into 'gluing', and - best/most important of all - enjoying it.