Who's that duck?

We went a walk over to Strathclyde Park today and spotted this pair on the loch. Does anyone know what they are? We can't find them in our bird book or online.
I still find it mildly stressful when people make no attempt to maintain a 2m distance when they are out for their walk. I am obviously still wearing my invisibility cloak - I used to wear it a lot pre-lockdown too!!