Idk what £ equals in usd but on ps store in USA its $30 for base + $30 for horizon $60 for base +horizon bundle when its not on sale
I don't have a PS4 so I cannot comment on their prices, but they seem to be a little dearer than frontier direct, and steam.
1 GBP (£) is roughly 1.27 USD ($) just now, and on the frontier webstore Base game is £20 / ~$25, so is horizons, and commander deluxe edition (Base + Horizons + some paints) is £40/$50. At launch of horizons it was £60/$75 for Base (£20/$25) & Horizons (£40/$50)