BB is a reputable brand, but so is Weyermann or Thomas Fawcett.
Any of their Pale Ale malts will do the job nicely and make decent beer, especially a Carlton Draft simile. You won't get the same malt as Carlton use anyway, as theirs would be specially malted to their specifications.
You'll notice more of a difference if instead of generic Pale Ale malt you use a variety specific Pale Ale malt something like Maris Otter or Golden Promise etc.
Don't get hung up on other peoples' recipes. Often they are made up with all they have available.Try things for yourself and go from there.