Oh Dear, I have seen some ready mixed Jeyes fluid somewhere and I cant remember where!
I know it was either Wilkinsons, crystal peaks, or Home Bargains on the Parkway. I think it was only last week, and thats the only 2 places I have been shopping. (apart from £land, but I can't see it being there, as it would cost more than a quid)
Could you not get one of those plant sprays and mix some up yourself? I think it might work out a bit cheaper too!