My father was sold a car with paint protection, which I thought was a waste of money, till I saw the results. My last car (bought early 2019) was delivered from Coventry, with paint protection, for £100. It was fantastic at keeping the white paint clean. Arnold Clark wanted £329 for paint protection for the MG3, which is too much.
I have opted for what I did for my wife's nearly new car, a very thorough wash and Autoglym Super Resin Polish and Extra Gloss Protection, which is a wax to go over the polish. The people who apply the ceramic protection with stamp sized applicators must have the patience of saints. The wax just pours on and spreads. Going by the wife's car, which is also white, it is long-lasting and the main difference between it and a professional ceramic protection, the water beads, rather than sheets, so it needs cleaning more often.