This is worse than having none for most people. 4 is too few in the UK, yet panels are the cheapest part of the system - I've seen them below £70! But to get new ones added you'll likely need to rip out the old, which adds cost to installing a proper system rather than helping you. Did you notice which way they faced out of interest? We've seen builders put them on the north side too despite the south roof having no obstructions!
If the government actually gave a shit about the whole net zero stuff they'd mandate better insulation and renewable measures for every new build. Why do we even have radiators nowadays in a new property? Instead they do this, madness.