Early congratulations. Unlike with (say) the Hilton equivalent, there isn't much fanfare, your My Executive Club area will discreetly mention the GGLfL, and you'll get an email from that nice Mr Hillier. Plus your CIV goes to at least 100. But that is pretty much it. There's nothing on the App, and the membership year dates all continues (for GUFs etc). Note that if you don't do any Avios transactions, then they can expire in the usual way, and you can theoretically be regarded as having a dead account through lack of transactions, but hopefully you are some way off that.