It does seem to be a pretty important resource to protect and has been very well used when I have been there.

Southwark Councillors may be saying that they should look at it for an expansion to the cemetery but they also have a responsibility to provide sports pitches for the borough. In my experience Sport England are VERY resistant to the loss of any pitches that are currently in use and have a lot of weight behind them in the form of Planning Policy Guidance note 17 (NB the Government is currently rewriting all national planning guidance and who knows what the new version will contain!).

http://www.communities.gov.uk/publicatio...guidance17

I would suggest contacting Sport England, also making sure that there are current and good records about how often it is used and by whom.

Good luck