Because some of our cats used to jump on the worktops too, we bought a special spray with a motion detector. The spray detects the cat jumping up on the worktop and at first will give a sound signal and after that it'll spray a harmless non toxic fluid.
I googled and found this site:
Cat Repellent Spray | MultiVet SSSCat Automatic Cat Repellent Spray
But I bought mine with zooplus.