That's interesting I was there yesterday. The keeper said they have six tigers and I spotted 2 Amur Malchek and Nika and two Bengal in adjacent enclosure Manas and Lahore. Just round the corner from there was an empty enclosure which had name tags Amirh and Indah it appears work is maintenance work is being carried out in here. However I believe it was indicated that these contained Sumatran tigers. Next enclosure along had two Sumatran tigers on display and I heard the keepers calling the female a name that sounded something similar to lydia.
Please forgive me if I have got any of the names or subspecies wrong I am not an expert and just enjoy viewing them. I have only just had my first few visits to Howletts in about 30 years.