Good point Phil ... but I know of a police motor bike rider , been riding for 30 years ... who had to re test as his licence came back without it on & they would not accept a copy
His advice ... before you send it off to get it renewed ... say you cannot find your old one , get a duplicate one & then send that off .. you can always *ahem* 'find' your old licence again if the new one comes back missing stuff off it
On the flip side ... I know another who came back with Full HGV after sending his off