I think you might find a Seneca V is in excess of £200k!
I remember seeing that some airfields in Pooley's specifically EXCLUDE 337s from landing (or departing, more like!) at their airfield due noise.
There was a 337 at Lt Staughton a few years back which was used for aerial photography but I don't know whether it was available for hire.
There also used to be one at Bourn, but that may have gone.