Yes, it is in commerce here.

Here is a link that might be useful: Bramley Apple/M7

You will be able to find most of your favorite British apples here. Besides Bramley Seedling, you can find Cox Orange Pippin (and any number of progeny that are more suited to our climate), and a number of cider apples like Tom Putt and Yarlington Mill.

Bramley did well for us even in a warm climate. We made apple crisp out of it (and I wish I had some right now).

Applenut

One feature of Bramley which makes it a good cooker is that the flesh collapses into ready made apple sauce almost immediately when you cook it up. No need to mash or sieve. Instant apple sauce. Brilliant apple for baking whole too. but no good for tarts, like French apple tarts, that require intact slices though. It does have a tendency to biennial bearing.