Thanks for contacting membership services.
We were awaiting the stock for the membership packs to arrive at warehouse - this took place last week for the adult packs and they began to be dispatched from there. And like you say, you have since received yours.
As no packs had been sent since the start of the season, there is currently a large backlog which we are making our way through. We are also expecting another delivery of stock for the junior packs, so bear with us. The details are up on the dispatch system for your son's pack waiting to be processed so it should go out soon.