It's entirely conceivable that he stashed the gold, it was subsequently discovered and stolen by somebody else (any of his relatives might have been in a position to do this, if for instance he stashed it in his home and they had reason to suspect he had done so.) Then, not knowing that the gold is gone he admits that he had it and agrees to turn it over, only to then discover that he cannot. What then is he meant to do?

The "balance of evidence" may say that he once had it, since he did seem to admit it when he agreed to turn it over, but what then? What evidence is there that he's now lying?

>"the balance of evidence "

Do not make me laugh. What evidence? Persons can and do forget most obvious things.

Dude I've forgotten computer passwords I've used 4-5 days a week for years; one day it was just gone.

> the judge will decide on the balance of evidence whether you appear to be telling the truth

Hmm, not sure if that's adequate, civil court is usually balance, and that's because it doesn't deprive someone of their liberty. Criminal court is beyond a reasonable doubt, because of the seriousness of the consequences