The beta in labeled G99xBXXU5ZVHE where "x" comes to the model that you have. All people who live in the UK and want to take part in the beta need to know that the beta is available for SIM-free models.
Don't worry if you didn't manage to take part in this beta, there are more coming.
If you are registered into the testing program you'll receive each beta as it is released, as an over-the-air update.