my husband is a tree surgeon and advised that the tree would need to be heavily reduced every 2/3 years to reign in the growth of the roots until it can be cut down. doing it in one go will kill the roots and collapse foundations. this sort of maintenance is very costly for councils hence their unwillingness to help. in the 'tree biz' lewisham is known for having poor maintenance.

found this for tree officers if that helps http://www.ltoa.org.uk/contacts/borough-...1-lewisham