I would be feeling blessed to have those guns and purchasing 2 1/2" shells would not concern me.
Some of my shooting buddies have been purchaseing the B&P Comp1 shells to shoot in their old doubles. One guy has a Purdey hammer gun in 2 1/2" chambers and he did the research and they meet the required chamber pressure. So he shoots them fine.
I recently just traded away a couple of English sidelocks and purchased a Purdey and an Atkin. Just so happens they are both 2 3/4" chambers. I would have bought them anyway even with the short chambers because they are both fine Best London guns.
So my opinion, in your afterlife when your wife decides to sell the person who will be buying them will be just as informed as you were (or not) and I am sure he will not have a problem have the chambers lengthened to 2 3/4" down at Joe's gunshop and gunsmithing.
Just hope she gets what they are worth.
