Thanks all,
I note web page headline now increased to £59 one way.
However, when attempting to book for next week price still comes up at £121.39 return (£92 plus £29.39). Also schedules page still showing 3 rotations per day.
I think I will wait a couple of days and try again. The whole site, including booking system, might have been updated by then.
I realise this airline is settling down and has now learned the best timings for the London runs from practical experience. Good luck to them and good to hear the non midday London loads are holding up well. Just the sort of thing an area like Wales needs. I hope Air Southwest is equally successful in the far south west.