4 times weekly? Who are they exactly aimed at? Surely not business passengers? BE/SN have many daily flights which definitely satisfy the frequency and times. Can it be for the tourism market? Is there enough demand for that? Or is it for a bit of both?
The times certainly don't suit me (leisure passenger / night owl).
But I suppose Ryanair's presence on the route will make flying to Manchester with SN/BE cheaper for me