How did kristian digby die?

Answer 1

The initial thought, as reported upon his death by the press, was that he died from a solo sex game that went wrong (which is most likely to be auto-erotic asphyxiation)

However, despite an inquest being opened in March 2010 there have been no subsequent updates. This suggests that either the initial suspicion as to the cause of death has not yet been confirmed for some reason, or that it has but his relatives want it hushing up.

It seems odd that a cause of death has not been reported upon, or if not yet established that a timescale has not been given to report it.

So, for now, your question cannot be conclusively answered.