Thanks Mike
All wader stock is poor at the moment, and its set to get worse before it gets better. Its a combination of lack of factory time in the east and a global lack of shipping containers. Its not the waders that are particularly the problem, though this is an issue for some, its also components, like zips and buckles. The shipping costs have gone up 600% in some cases so lower cost bulky items are no longer viable to ship, as their price point would soar. Heavy boxed neoprene waders could be a problem for some time, i am told it could be September before all the usual lines are available again. Many of the suppliers are trying to avoid having to put a chunk of cost onto their waders as it would kill them off, so its actually better for them to simply not ship them for now.
For cold weather you have a couple of choices, i have a very small number of warranty replacement stocking foot neoprenes, but for very cold stuff dont rule out breathables. Remember neoprene is an insulator, it will keep things hot or cold. With modern base layers, thinsulate insulation and the like you can easily keep as warm with a breathable as a neoprene. Back in my diving days we woukld dive under ice in thin suits, like breathables but 3 times thicker, but we would have 4 properly designed layers beneath the suit. This may give you a few more options for which is, i hope, a short term problem.
D