Sunday roasts are hard to get right, and even some of the best restaurants and pubs in the land still manage to do it averagely. The best barometer is not the Yorkshire puddings. Everyone seems to be able to deliver hat-sized Yokshires these days.
The same goes for beef pinkness. Anyone can undercook beef too, and you can always heat it through again for people who prefer it a bit less abattoirial. Without a time machine, it’s a lot trickier to make overcooked beef pink again.
No, it’s all about the roast potatoes. If they’ve got them right, you can be fairly sure that they’ve got everything else right too.