BA has agreed to pay all of my expenses - not that big a surprise. Unfortunately, my email wasn't passed on with a clear explanation as to why I am claiming compensation for the cancellation and the downgrade. Having to use the reply to webform is a very poor user experience, but I have pasted in my original email and sent that off to BA. That's wasted 10 days. Hoping for a more productive response from BA to my claim for compensation.