Conkers are maturing nicely - but how long for?

There's a wonderful mature horse chestnut tree on my favourite walk in the hills around Peebles.  It's already covered in maturing conkers.  The usual question regarding conkers is how best to harden them for the game of the same name - a brief dip in vinegar or a whole year pickling?  Or a bake in the oven?  Some think all this is just cheating.  

However the key question now is how long it will survive.  Leaf-miner moth arrived from the continent of Europe a few years ago and is decimating trees throughout the UK.  Once affected they typically die in 3-5 years.  Thankfully this one seems free of them - so far.