Danny
I let my SEP rating lapse by 1 day a few years ago. Unfortunately, like me you will have to revalidate by flight test. The good news is that it's a shortened version of your PPL GST.
"Typically" consisting of a small nav trip, general handing including stalls, PFL, steep turns, spiral dive recovery etc. Then back for 3 circuits, again, typically a "normal, flaples & glide.
That's it.