Putting Redex in is easy peasy as putting fuel in

Next time you FILL your tank put in the recommended amount of Redex in, which is usually 1/2 bottle to a FULL tank if it's the 250ml bottle.
Also try running Tesco 99 ron through, when I use that it makes my car so nice and steady and does not feel 'jumpy' when crawling at 1mph
You probably still have the Pierburg car fitted, they are apparently really bad

People replace them with the weber carbs