http://bluesaway.org/index.html - Blues Away, need to be a member but its free to join - £18.
The Seagull Travel coach from Eastbourne looks like it is now sold out too.
It is 100% closed and NO Southeastern service will run on any of their routes. Good luck getting a Southern train from...
You can use public transport to get there, but its an arse.
Hourly service on the trains between Brighton and Three Bridges will connect with a replacement bus to East Grinstead which will connect with a train to London Bridge. Change at London Bridge for the Jubilee Line to North Greenwich and...