Because offshore kennels are the latest legal tax avoidance scheme. Or because the monies turned out to be a gift, after some investment scheme of his and his co-defendant fell through. Or because, as a journalist taped him as saying, it was a bonus [and therefore taxable] for his selling a player, and legitimate under the football authority's rules against improper payments ('bungs'). At his trial, he said he lied to the journalist but, given his proclaimed ignorance of finance, could it be that he didn't know then that he was admitting that he'd been depositing taxable income? The Revenue thought so.
Why Monaco ? Now there's the question. There was no reason for the payments to be put in an account abroad, if any of Redknapp's versions were true. Why the dog's name? To open the account he must have used his own name, passport etc, to comply with the law there, but he could call it whatever he liked. He liked his dog .