The GLA route picks up most passengers at Plymouth - probably why flybe didn't have much luck competing with ASW. When Plymouth closes, the passengers are more likely to go to Exeter to fly to GLA so I'm not sure how successful a NQY-GLA route would be.
Does anyone think that an airline would start up a route in October to NQY? - surely they would wait until Spring/Summer of next year. They might also struggle to fill a Q400 size aircraft on all the ASW routes into NQY as both PLH and NQY relied on filling the load sharing between the 2 airports. A 737 works with holiday traffic to MAN and might work for DUB but I doubt many of the other destinations could.
In 1994 Newquay Air(who became the first Air South West) operated a PA31 from NQY to ORK, DUB and JER 4 times a week with some of the flights even operating via Exeter. In 1995 they dropped NQY in favour of EXT. In 1996 they dropped EXT and moved to PLH!