Potatoes, advice please!

I thought they were just called baking potatoes because they are large and therefore more suitable for baking than small potatoes. Also, they are not "waxy" potatoes but the insides go "fluffy" when baked in the oven so I would imagine they would be suitable for roasting.

I'm no expert though and perhaps someone else knows for sure.

Is the variety name on the bag, phoenix?

I would test one if you're not sure. If it holds its shape during parboiling I'm sure it will be fine.

You won't ruin Xmas dinner. The ones we had (roasted) today had just started sprouting some tiny shoots. They were delicious. Pop 'em in the fridge till Friday, if you've got room.