The commercial growers here in Angus have been planting main crop for about a week now, and still at it, so it's definitely not too late. We time our planting based on what they do, I have most of ours in with a few rows still to plant.
If anyone in the Carnoustie area wants Rooster seed potatoes we've got dozens to spare - a friend gifted us 3 large trays, and we've only got room to plant about 100 of them.