This is one of those cases where there are three hostas with the same name. One is registered and, therefore, the "official" version of H. 'Hydon Sunset' while the other two are non-registered plants and need to be renamed to avoid further confusion.

This is a hybrid of Hosta gracillima x H. 'Wogon Gold' was registered by the British Hosta and Hemerocallis Society in 1988 on behalf of the originator, Arthur George of Hydon Nurseries in England . It grows into a small size hosta about 8 inches in height with a spread of 22 inches. The leaves start the spring gold and turn green as the season progresses. They are slightly wavy and have average substance. Purple flowers bloom in July. 

We call this plant 'Hydon Sunset' (George).
 

Another plant with the name 'Hydon Sunset' is also found in gardens. These plants emerge yellow in the spring and maintain that color throughout the season. Mark Zilis says that these plants are actually mislabeled specimens of H. 'Dawn'.

We call this plant 'Hydon Sunset' (Yellow).

Mark Zilis also found hostas in various gardens that were labeled 'Hydon Sunset' but develops into a large mound of plain green foliage.

We call this 'Hydon Sunset' (Green).