Hello Sorcha,
I don't think that this will help you much, but here goes....
You don't state what time period you are interested in but I presume it would be somewhere around the Great War (First World War).
I'm guessing that your GGUncle was in the R.A.F. as in 1919 Somerset house was listed in the local street directory as:
"Government Offices (Royal Air Force Midland Area)"
This is what the directories show from 1911 to 1922:
1911
14 Clarendon Place, Somerset House
A & Miss Barratt
Misses Barratt Kindergarten
1912 Ditto
1913 Same as above but without Miss
1914 Ditto
1915 Ditto
1916 Ditto
1917 Ditto
1918 No Directory available
1919
12 & 14 Clarendon Avenue
Government Offices (Royal Air Force Midland Area)
1920 Ditto
1921 No Directory available
1922
14 Clarendon Avenue – Void (presumably empty of occupants)
16 Clarendon Avenue (appearing for the first time in the directory)
Somerset House Chambers
- Hosking R.V., house agent
- Wharrad C. & Co., agents
- Cookson W. B., accountant
- Mansell E., F.R.I.B.A. (Mansell & Mansell architects)
- Woodhouse T., architect & surveyor
I go past Clarendon Place on my way to work each day, but I've never paid it much attention before. I'll make a point of looking out for Somerset House next time I pass by.
Regards,
Tim