Links
L.C.A. - The Lead Contractors Association Member
L.S.A. - The Lead Sheet Association
R.I.B.A. - Royal Institute of British Architects
British Lead - the greenest building material 
ELSIA.org.uk - 'Lead sheet - time to dispel the myths'
Building Conservation - repairing lead sheet article
Ecclesiastical and Heritage World - Lead industry mounts a Europe-wide offensive
Project Book - Period & Listed Buildings Resource
Lead roof in Kensington, London. Celtic Leadwork.