Thanks for the responses guys - keep them coming.
Regarding my original crank: this is 118mm BCD, which (according to Sheldon Brown) is now an obsolete size.
The objective was to go for a flip flop with 68/65 gear inches, hence the 44t chainring, which, coupled with 17/18 sprockets would give (more or less) the desired result; however, I suppose I could increase the chainring to expand my options. Perhaps a 47t (with 18/19 sprockets) would provide the same ratio, with more options for the crank? The Holdsworth appealed as it looks the part and is not too pricey, but 144mm is a less common BCD so may be more difficult to upgrade later?
Argh overthinking again!