I use auto smarts Duet wash and wax soap once a week, that's after knocking the rough off with weakish TFR soap. After that it's out with the wax it wet from autoglym.
For a deep clean I use evo3 cutting compound from auto smart. Use an electric buffer and plenty of water in a spray bottle with a drop of wax it wet mixed in for better lubrication. Then out with the auto glym resin polish to finish.
Not very environmentally friendly but the best thing to remove tar from paintwork is diesel, just wipe over the top with a sponge till it dissolves, no damage to the paintwork either 😀