What makes you say that? I don't think she looks miserable, just due to an excess amount of peanuts. This is only the moat to the huge woodland exhibit also seen in the gallery.
Or perhaps she's just "nodding off" because she is tired after playing in her large enclosure. The fact that bears' expressions are virtually unreadable does not really help your argument.
None taken! Just try to consider all the options next time. Universally there are only four human facial gestures that convey the same meaning. Therefore, assuming that we know what an animal is thinking is very dangerous territory!
In the new owner's book he talks of drastic dieting and dental work to sort these bears out after a lifetime of junk food [which I'm sure they enjoyed]
The bears didn't use their wooded enclosure that much as they would spend most of the day begging for food in the sunken dry moat at the front of the enclosure. Fudge and Hayley, the two original bears (a third was brought in about ten years ago) had lived in a tiny pit attached to the side of the house in the centre of the wildlife park for many years, so may have been more used to looking up at visitors and begging for food.
I suspect that behavioural enrichment has improved since the current owners took over, and the enclosure appears to be utilised more fully now the bears can no longer expect to be fed by the public.
I must add, in Ellis Daw's defence, that the enclosure, built during his time as owner, is fantastic.