This is the same bird shown in
SD7706 : An Uncommon Visitor.
The mandarin duck (Aix galericulata), or just mandarin, is a perching duck species found in East Asia. It is medium-sized, at 41–49 cm long with a 65–75 cm wingspan. They were introduced to the UK from China and, following escapes from captivity in the 20th century, a large feral population became established in south, central and eastern England; more recently small numbers have bred in Ireland, concentrated in the parks of Dublin.
The male has the most elaborate and ornate plumage with distinctive long orange feathers on the side of the face, orange 'sails' on the back, and pale orange flanks. The female is dull by comparison with a grey head and white stripe behind the eye, brown back and mottled flanks.
Link RSPB