text: Probably not a spelling error, but a contentious historical alternative (like Lee Valley and Lea Valley). Barking and Dagenham historical society spells it with an A but Dagenham Council spells it without.
  
  Wikipedia says "Becontree Heath (also spelt Beacontree Heath)". 
  
  I think on balance it should probably be spelled without but the A version added as an alternative. Have done that provisionally -- if anybody objects, please re-open and comment.
  
  
  