So now we have an electric connection (7 days and counting) I've started to run the MVHR unit 24x7 but since then we've started to notice little flies in one room.  Having pulled off the MVHR supply air vent in this room it contains many of the little beggars trapped in the foam as per photo.   Two weeks back I vacuum cleaned the MVHR filters, apart from being a bit dirty with 12 months of limited use there were no flies, today the exterior filter contains a few of the same flies (whic