Midwinter Antiques has dated this piece to the 1850s.
The leather is original and so is the protective slide in front of the secretaire drawers and all the inset brass handles.

It is an exceptional piece, the burr walnut giving it a lovely warm colour. It has an interesting provenance having belonged to Captain J.H. Gaitskill of the 106th Bombay light infantry, serving from 1862-68
Midwinter Antiques has dated this piece to the 1850s.
You can view the stock and full dealer information on the Midwinter Antiques Profile Page