This is a bizarre claim:

He foresaw that China would reclaim Hong Kong 12 years before it happened

It's might be just a typo, but I penalize BdM for it. Britain and China negotiated the hand-over 13 years ahead, so 12 year predictions are unimpressive. Wikipedia dates the negotiation to the governor's 1979 trip to the mainland. (This comment seems to acknowledge but deny that version of history and instead put the focus on 15 year mortgages, which does match the 1982 beginning of serious negotiations. Yet earlier citizenship bills suggest that UK was planning for the handover.)