If you don't ask you'll never know.
Pointless phoning beforehand, (Essex Radar is done from Swanwick these days if you didn't know that.) Looking at the track Cambridge to Southend it goes through the rwy 23 approach so if they are busy on that runway, probably not. Prob most preferred option is over the top at right angles to the runway but that is probably more miles than going around the CTA to the NE.