Currently (with some collections missed off, I'm sure):
Gaur: Whipsnade
Banteng: West Mids
Lowland Anoa: Chester, London, West Mids, Marwell, Port Lympne (any others?)
'Asian' Water Buffalo (whether domestic or wild is debatable): Port Lympne, West Mids (Longleat?)
Cape Buffalo: Knowsley, West Mids
Congo Buffalo: Chester, Knowsley, Woburn
American Bison: Woburn, Whipsnade, Noah's, Blair Drummond (I'm sure there's more)
European Bison: Whipsnade, Howletts, Port Lympne, Highland
In terms of wild taxa, the only taxa present in Europe but NOT the UK are the Mountain Anoa (Bubalus quarlesi) and the disputed subspecies, Wood Bison (Bison bison athabascae).
The UK also has various breeds of domestic cattle - in addition to good old Bos taurus in many forms there are also Heck cattle, yak, water buffalo and zebu (but not to my knowledge Gayal, which can be found on the continent).