Certificate of Revalidation' similar to those in my UK PPL which I get signed every two years when I complete my bi-ennial check.
There is no bienial check; you simply do a training flight or series of flights with an Instructor who signs your log book.
The Certificate pages are in your licence because the CAA only have one format for printing licences and in the case of the LAPL are totally surperfluous.
So long as your log books shows your currency and the 1 hour training within the past 24 months you are legal. Any EASA FI or CRI can do that. There is no expirey date or validity shown in the licence.