On the surface, that's seems like nice sentiment, but on deeper analysis it's not. Firstly, all british broadcasts are already controlled by the people with deep pockets ( including the government funded state propaganda BBC ). Secondly, british media is extremely biased already. Thirdly, all this does is just helps the entrenched old money control the narrative. Fourthly, china, the soviet union, nazi germany, etc also banned political adverts.
At the end of the day, it doesn't really matter. The people with the most money and power will win whether you ban political ads or not.
Democracy, whether here or in the UK, is controlled and managed and provide an illusion of choice.