Hi, Corkcutter,
Thanks very much for that. Hadn't realised this job was so specific to London. Have been to The Guildhall Library several times before - a wonderful resource, especially for London Directories; had no idea they were having a re-organistation there. London Metropolitan Archives is practically opposite the Family Records Centre, so when things are a little calmer at King's Cross I'll take a train there, then stroll down to the LMA and have a browse through whatever they have...
Very best wishes,
Keith