I don't quite follow the idea that Air Southwest would do NQY-BOH-MAN or PLH-BOH-MAN when they already fly to MAN from PLH via BRS, and from next April NQY pax will also be able to reach MAN by changing at BRS.
I can't see this airline effectively duplicating these routes.
However, BOH might well prove attractive to them for other destinations, either for flights commencing at PLH or NQY or even from BOH direct, because there can't be many further options for them at BRS given that most destinations from there are already flown by others.
I would still like to see them do BRS-NWI and BRS-ORK though, because Aer Arann don't seem much interested in the latter route.