I did work one or two on that route when Manston weren't doing radar, could even identify on radar using Pease Pottage radar feed, but 'officially' it's outside the LARS East area of operations so todays controllers might not be as willing as I was to actually provide a service (I saw nothing wrong provided I wasn't treading on somebody elses toes; it was safer for you guys just in case there was a sudden silence up front I could alert D & D).
You should be able to get 2-way with Farnborough however and ask them to pass a message to London Info on your behalf even if they're reluctant to do anyhting else for you.