Hi

I don't think it's L O b. I say it's definitely L o C - UpperCase L, lower Case o, UpperCase C.
The Agent & Paymaster is Messrs Cox & Co, not Box & Bo.
The b in Wetherby is quite different, is lowercase and is not an initial letter. That 'b' is a standard lower-case and the C in Cox a standard upper-case in that cursive style of writing.
The writer is using 2 different, but quite 'normal' styles of B and C :
See: C in Camp & in Lt Col. & in I.G.C.
See: C in L o C , in Cox & Co & in Commandant
See: B in VB Ripon
See: B in Ford Bank
Cheers
AMBLY