Redex diesel cleaner usually £4 now half price, I use this regularly in my diesel bimmer which helps reduce smoke and I get a few extra mpg!
Not sure if this is local but Tesco online it's £3, usually £4!
Instore only went looking for the rainx deal which I couldn't find.
Tesco Holmbush shoreham
Tip- try not to get it on your hands as it stinks and takes a while to disappear