(there's the added bonus of the runway length that can take anything that's flying at the moment)
RSOL,
You talk about cargo operations and St. Mawgan's runway length being able to take anything that is flying at present?
I think you need to go back to the drawing board, cargo aircraft do not carry 'lightweight' passengers, they carry cargo and often up to max payload, a lost kilo is lost revenue, and thereafter live in hope that they can get enough fuel on board, up to MTOW, to make it to their next destination and/or refuelling stop.
I recall occupying much of a night shift once trying to plan a max payload DC8-62 from Europe to the States, our normal refuelling point would have been Gander however eastern Canada was fogbound.
We obviously had to plan to the first point in USA, Bangor, but needed to stop, beforehand, in SNN or PIK and PIK has a significantly longer runway than NQY. The DC8 couldn't get to BGR from SNN and, even using standard flap settings couldn't make it from PIK, I needed to plan non standard flap settings and even then it needed, literally, every inch of PIK's runway to get off the ground and the crew commented so afterwards.
And if max payload aircraft are to take a southerly track across the pond, as we then sometimes looked at options of, then there is Brest airport with a more appropriate runway length than NQY.