For the first time in many happy years of use my walking boots let me down resulting in very wet feet. Should I have been applying some kind of leather treatment and if so what is best to try and restore their waterproofness. The boots made by Crispi and are full leather with no membrane.

Yes, you should have been using a wax such as Grangers or Dubbins to keep the leather supple and stop it from cracking. it prolongs the life of the leather and helps shed water.
There are plenty of brands out there, just pop into your local outdoor store (Cotswolds etc) and see what they’ve got

Scarpa HS12 cream is quite good. I find it goes on better than the Grangers and NikWax stuff.

Altberg Leder-gris is pretty good

If they’ve started leaking is it not too late? I thought the point of waxing was to keep the leather supple and prevent it cracking and leaking. Don’t know if waxing them would seal the leaks…

This was my worry 13thfloormonk. The leather does still seem in good condition though. It’s still supple and hasn’t cracked. I’ll pick a re-proofer and give it a go. I suppose the worst that can happen is another day with wet feet.

Scarpa HS12 is great, expensive mind. Certainly better than other leather treatments I’ve used. But prolly too late, it’s a preventative not a cure.

I use sno-seal depends how they are leaking really dunnit.

I suppose the worst that can happen is another day with wet feet.

I had to put up with leaking boots for a while, SealSkinz mid weight waterproof socks made them a lot more tolerable, add some liner socks if it gets too cold with them alone.

FWIW Waxoyle is the same as Grangers and a few other treatments so if you own a Land Rover or an old British car and have some Waxoyle, get Waxoyling.