Great work.
Nigel Brown has a G. Spittle and a George Spittle listed in his book British Gunmakers: Volume Two.
G. Spittle was a lockmaker, Wednesbury Staffs, 1864
George Spittle was a lockmaker, 80 Longacre, Nechells, Birmingham 1857-1860 and New St, Darlaston Staffs, 1867-1870.
There are a number of other Spittles listed in Brown's book.
They were in the lock business as early as 1816 and stayed in it until around 1897. It looks like locks were a family business for them.
Of course, the pull-down forend latch was patented by Deeley & Edge in 1873.
Odd that the locks are non rebounding...
OWD
