Apart from the A320 Charter to Dublin a couple of months ago, I think Thomsonfly accounts for 100% of passengers through Coventry. I think the only time when any other airlines express an interest in Coventry Airport will be when/if the new 2 million passenger terminal is given approval.
The leases on the 4 CVT based 737-500s are to expire within the year. Coventry will then receive 4 737-300s indicating an increase in capacity.