Of course you will have checked your notams won't you? The atmospheric research aircraft quite often does a low level 'round the coast' run and it could ruin your whole day to find a 146 coming the other way.
I've several times had a heads up from the kit to see the Isle of Wight passing by. They are probably talking to Solent so listening in may be helpful.
If you have internet access for your notams then you could also look at the FAAM website and see the flight plan for the day, and even a real time position plot if its already airborne.
Jim