[3] William Wallen Senior practised as an architect and surveyor, however; he appears to have favoured surveying commissions.
His career was somewhat overshadowed by his older brother, John Wallen (1783–1865) who was an architect and the principal surveyor to London during the 1830s.
It is also suggested that he was the “Mr Wallen” who received a substantial fee for the survey and probably the design of Claremont Chapel in New Road, Pentonville.
This was probably an arrangement between Vulliamy and Wallen to equip Jones with essential surveying skills before he undertook a Grand Tour of Europe and the Middle East in 1832.
In Wallen v. Smith he successfully appealed costs exceeding £40 previously awarded against him.