Abs! Looky! I found it – and right where you said, organic section of Asda :)

I confess, after years of doubting the existance of veggie ‘wooster’ sauce, I was starting to wonder if sod’s law would kick in and having found it, I would find the stuff disgusting. But it smells interesting – in a good way – so now I’m just looking for the appropriate first taste trial :)