@WillFalstaff You can use leather wax. I use a thin coat of petroleum jelly. Cheap and gives a good result. Used it for more than 40 years to preserve leather liners of German helmets.
@Bruce Pennington Hi Bruce,
I've been trying to find more information about the RAF soldier. I can only find one G.J. Southard, but without access to his service records, I don't know if this is the right person.
Regards, Ed
The latest addition to my collection. Old blade, civil tsuba and an inscription by a soldier of the RAF Regiment on the leather combat cover. G.J. Southard RAFR Malaya 1945.