Style of architecture old lady found around Clerkenwell area? (7)
I believe the answer is:
grecian
'style of architecture' is the definition.
'old lady found around clerkenwell area?' is the wordplay.
'old lady' becomes 'gran' (I've seen this before).
'found around' means one lot of letters goes inside another.
'clerkenwell area?' becomes 'eci' (resembles EC1, London postcode).
'gran' placed around 'eci' is 'GRECIAN'.
(Other definitions for grecian that I've seen before include "straight sort of nose" , "Attic" , "classical style" , "Hellenic" , "Classically simple - in grace (anag)" .)