I bought this when I was in England. Does anyone know where to get it in the US?

Its made by Kelkin and is called Kelkin Gluten Free Porridge.

There are very few places to get gluten-free oats in the US, because they are usually processed in the same facilities along side wheat. Also, the CODEX standard (which Europe uses for food labeling laws) allows for a certain amount of gluten, which many turn out to react to.

Some Celiacs can have oats, some cannot. If you know you can without the immune response, try Googling for gluten-free oats.