Can your vet get it for you? If they use science recovery they might be able to order some in for next day as it will presumably come from the same stockist of supreme products. I think our local Wyevale stocks it too - is there one of those near you (how about the one that used to be Roots n Shoots on that road between Upminster and Brentwood, I forget its name). I can go and have a look in the Chelmsford one tomorrow if you're desperate - or I have plenty of normal SS I can send your way if you need.