Now, this may be me over-simplifying, but I wondered, do we all get our supplies from the same place?
I use a well known on-line stockist for my Frontline supplies, I don't want to name/blame the suppliers as they've always been very reliable and the Frontline they supply has always worked until quite recently. I'm wondering about a bad batch?
I've decided to use Advantage this time - doing a "scientific" test - four cats (Tufty, Beau, Sam and Sly) on Advantage, three (Theo, Pursley and Chubby) on the usual Frontline. I'll let you know how we've got on in a week or so.