Late in 1965, the phased move to the (then) new company-built head office (at 86-88 Upper Richmond Road, Putney SW15) commenced, although, when the writer left to move to Canada in December 1965, the cost-accounting department run by the great Sam Shinwell was still based in 6, Lambeth Road.
(Of possible historical note is that, having remained vacant for several years, planning permission for the demolition of 86-88, Upper Richmond Road was granted in 2011 by Wandsworth Borough Council with the intent that the site be occupied by a new development.