'I hope you have a good time at Nottingham.'
'I hope she will have a good time at Nottingham - though I have my doubts.'
But when the wish is for the future, the past tense isn't acceptable. In 'I hope he had a good time in Brazil. We'll find out when he wakes up' the wish is not for the future (it's about a future conversation - or other means of discovering - about a past event).
Student or Learner