Make sure the Mrs knows roughley how much items are worth or your friendly RFD who you've spent many thousands of pounds with might offer £500 for the lot as a favour
Avoid choosing a complicated hiding place,otherwise your executors will never find them and you will probably forget where you put them. Equallydon’t leave your keys on top of the cabinet as this would just make them a present to burglars.
If you know your RFD well they may give you authority to transport the Guns to them for storage (once you get in the cabinet etc) as a Servant of them under the RFD there is no paperwork this is what i did for my father in laws guns told the RFD (family Friend) the day I was to transport the guns to him and If stopped by the police inform them I was transporting the Guns under his RFD and to contact him to check etc
Funny Thought came to my mind ? I only wish I could see the wife's face when she looks at the sales receipts as to what the real cost of my toys was "look love I got this for £100 all in ? A S&B scope, rifle, bipod, sling, gun case, ton's of reloading gear to last years oh yes and I got a free stalk !!!