Not sure if any lock cases conform to BS:2004 yet but remember you won't get a BS rated lock case on it's own as someone could install a super duper strength BS rated lock case and then pop a massively oversized Contract cylinder in there that sticks out an inch and has no escutcheon.
There are BS rated lock cases, not the latest standard, that come as complete kits like the Walsall from SKS that comes with boxed strike, cylinder and security escutcheon.