Many thanks for your reply Dawn, luckily I only live about an hour from London so can visit from time to time.
I'll send a mail as you suggest, I've been researching the Royal Brompton Hospital trying to see when the site spread as large as it is today. In 1911 there are two households listed at 93 Sydney Street but that house may have been demolished and the land used by the hospital by the time my relative died 'on the way to 93 Sydney Street' in 1930.
I'd be very grateful if you get a chance to look at the LMA, I have visited there last year but doubt I'll be able to go again til later in the summer.
Thanks again, Heather