Sir Jeffry Wyatville RA was an English architect and garden designer. Born Jeffry Wyatt into an established dynasty of architects, in 1824 he was allowed by King George IV to change his surname to Wyatville (frequently misspelled Wyattville).He is mainly remembered for making alterations and extensions to Chatsworth House and Windsor Castle - see his entry in Wikipedia.
As Jeffry Wyatt, he planned changes to Towneley between 1812 and 1819. Around 28 of his plans survive at Towneley in the documents collection, 24 of which are signed Jeffry Wyatt. There are also two watercolours by him in the collection, being designs for altering the East and South Fronts of Towneley Hall. The main changes that were actually implemented were to the South wing and the addition of the porch and servants' passageway running along the East front.
For a detailed account of his work on Towneley see Chapter 6 Peregrine Towneley and his architect Jeffry Wyatt in "An Architectural History of Towneley Hall" by W. John and Kit Smith, published by Heritage Trust for the North West in 2004.