Alan,
Lots of considerations there, having been through that pain barrier of insurance.
I let the 4T go, in its chest full CES some years ago for £4500 and that was cheap at the time with provenance.
I sold my L42 in its chest and FULL CES for £9500 recently with provenance as it was used in the Falklands by a 2 SCOTS sniper and the rifle behind the book FALKLANDS WAR: SNIPERS DOWN SOUTH a book I wrote for two charities with Frank Fletcher.
It is as Roger says............in each case the buyer held the rifle and examined all components carefully. It is essential, especially in these UNIQUE rifles which is what they are.
IMHO I find the buyers and sellers fees extortionate.
It would be far eaiser to sell it on here and give Doug 10% of the sale for this website............but thats my view, and many experts on here would assist and steer you to a good buy, that will only go up in value.
Insurers are pretty hard to deal with as noone really knows what you have in your custody, they just give a base figure as long as their risk is minimal!!