Hi, and welcome to the forum. I haven’t heard about the licence renewal as you describe it. Normally, you would have a medical, complete the D2 and your licence will be re-issued. Medicals are easy enough to get now.
You will need to complete 35 hours of driver cpc. This is normally 5 x 7 hr sessions held in a classroom. Online options are available temporarily due to COVID. Classrooms are open again. (For me, I’ve rented a church hall to ensure 2m social distancing).
I would also recommend a refresher course. Things have changed drastically with vehicles over the last 30 years.
Let me know if I can help further, Pete 