As part of the plans by the Boundary Commission for England, they propose for Forest Hill to be part of a new constituency that would include Lewisham West with parts of New Cross and Peckham, but would lose the Penge and Anerley part to a new Beckenham seat.
The constituency would be called ‘Peckham and Lewisham West’ if approved.
This is all part of the scheme to reduce London seats from 73 to 68.
You can look at the proposed map at http://www.bce2018.org.uk/node/6485?postcode=SE232XH
SE23 residents on the Southwark side of the border would all become part of the Dulwich & West Norwood constituency which is currently split between Dulwich/West Norwood and Camberwell & Peckham.