On Saturday they had somebody trespassing on the line at New Cross Gate, and then signal failure yesterday.
As a result I have learned how to travel back from New Cross on the buses:
Take the 171 or 172 from Marquis Of Granby (bus stop T) - half way towards New Cross Gate http://www.tfl.gov.uk/bus/stop/490009689...-of-granby
171 will take you to Stanstead Road, where you can pick up the 185 or 122 or 176
172 will take you to Honor Oak Park where you can get the 122 or the P4 (if you're heading in that direction)

For greater disruption, to get from Canada Water or Surrey Quays to New Cross you can take the 225 bus, which runs at 15 minute intervals.

Alternatively from Canada Water you can get a Jubilee line train to Canary Wharf, change to the DLR and head to Lewisham, where you can get the P4, 122, or 185. TfL suggest this as the fastest route but it will take over an hour.

Any other suggestions on routes to get home with no trains and without stealing a bicycle?