The shop at Staylittle should keep you going, don’t expect loads of choice but enough basics to keep you going … Nick the owners a really nice bloke too, you’ll get a much friendlier reception than if you go to the Star.
If I’m not working I might just take you up on your offer … If the weathers not playing, may I suggest using the descent from the memorial on the mountain road rather than Foel Fadian. It’ll drop you out within a 1k of Foel Fadian and it may help you keep your sanity 😉