As far as I'm aware the last remaining breeder of this species in Europe hasn't sold any Cape shoveler to any UK collections but has to zoos such as Cologne.
I would be more than happy to be proved wrong but I feel this is more likely to be a male Cinnamon teal in eclipse plumage.
@Prochilodus246 that was another one of my suspicions. And it does make more sense given the zoo mainly has species fairly accessible in aviculture or the exotic pet trade
Unfortunately, it is likely that this individual is not a Cape shoveler given the breeder is interested in still keeping the species around in European aviculture and would have unlikely offered to sell single birds given there is very few birds still around.
@komodoskar
I hope so too but as the breeder said when I made a visit is nobody wants a brown and drab shoveler when there are far more beautiful species more widely available.