I've looked at these sort of things a few times when people have mentioned them, and come to the same conclusion: they're eyewateringly expensive.
I just Googled Oakhouse, and at the top of the page for example was this
Cottage pie: it's £13.21 per 1000kcal (£4.90 for 371kcals). Compare that with my own cottage pie recipe: £1.99/1000kcal (£1.56 for 783kcals), and £1.20/1000kcals for my diet overall. That's 6.5 times the price, which is comparable with the recipe kits I priced at five times the cost last time I looked at this sort of stuff. It also has three times the salt, twice the sugar 50% more fat, and a fraction of the veg.
They're fine if you want/need convenience at any price I suppose.