Marco, thanks for the advice. I fear it is not doing my mental health much good worrying about such situations...! FYI have ridden a track bike at a couple of velodromes, a few times but would by no means count myself an expert on such matters.
Anyway, after today's dalliance into the 18T gear ratios and maxing that out before I'd got into my stride, I have decided that 46/16 is the way to go. Bike ordered tonight and hopefully arrives next week.
Of course I reserve the right to stick an 18T on in a couple of weeks....