Also these stations have one train a day not calling: Glan Conwy, Dolgarrog, Pont y Pant, Dolwyddelan, Roman Bridge (the 0515 Llandudno Junction to Blaenau Ffestiniog)so, with the Lowland sleeper that is 4 non-stops... Looks like Newton Abbott, Coventry and Prestatyn (p.s. and Wolves) win with just 1 train not calling per day each? Preston has the sleeper in each direction.
(I don't think trains on diversions really count, and NTA looks like it might be sneaking in with a summerSaturdaytimetable train.)
edit - plus Colchester!
Prestatyn is one a week, not one a day, so it beats these.
