The only Langley I've come across is near Witton Gilbert and I've covered those families quite extensively. The surname was fairly consistent as Croudace, but I'm convinced that the families in the Ferryhill area are related and their surname was usually given as Cruddas but very inconsistent. I've got those covered as well.
I've been checking some more of my notes and found a William Croudas baptised in June 1816 at Durham St Nicholas but unfortunately he was buried in October the following year.
A couple of items that you might not have -
Marriages at Staindrop
15th May 1823, Robert Cruddass of Bd Castle to Elizabeth Stoddart
13th April 1828, John Lodge & Ann Cruddas of Staindrop
Burial at Barnard Castle
28th Sept 1809, Isabella, age 24, dau of Robert Cruddass & Martha late Harker
(Could she be a sister of William's dad?)
Death Notice, Darlington & Stockton Times, Feb 11th 1922
feb 2nd at Thorpe, Robin Hood's Bay, William Cruddas ex Police Constable, aged 70, youngest son of the late Thomas & Sophia Cruddas, late of Wood End, Streatlam Park, Barnard Castle.
Perhaps it might be better to continue through normal email. If you agree can you send a PM with your address.
Regards,
Colin