UK bank affordability test already bake in a component of resilience to rate rises and the binding constraint for most people is an income multiple limit or raising a deposit. As such affordability has a lower dependence on rates than you might expect(and certainly nothing like your model). Probably the biggest impact so far is banks starting to withdraw 95% LTV deals.

So when do you expect the 30% drop in prices? I assume you have sold all property and found a way to short real estate since you seem to think the outcome is so certain?