Thanks all. I wasn't sure if the DOC came with the position or the assigned frequency.
Leeds Tower ATC is something of an anomaly. There is enough RTF traffic to justify two positions but the lack of taxiways (no parallel after all these years) means GMC is largely pointless. So the Tower controller isn't overloaded, the assistant provides clearance delivery, except at night or at quiet periods during the day. They've been doing this for about fourteen years. The existence of SIDs must simplify matters.