It's a bit tough (at least in the Canadian market) to put a value on something unusual like this commercial CLLE. I put one similar to it in a large auction and got less than a nice SMLE might bring. Patience and selling in the right venue would be necessary to get full value for one of these. Posting one for sale on this website would certainly get lots of knowledgeable collectors looking at it. For insurance purposes you could simply go with an average Ordnance "Long Lee," assuming that would cover your sunk costs?

Ruprecht

 

Very nice rifle. Your rifle was made by the London Small Arms Company, but was retailed by W.J. Jeffrey & Company. I have a Lee Speed 'Long Lee' made by Birmingham Small Arms Company, & retailed by William Powell & Son, Carr Lane, Birmingham, but engraved on the dust cover rather than the barrel like yours.

 

Here are some cleaner photographs that my friend sent me before I purchased the rifles.