Maybe Saint Helena or the Falklands need a new governor?
Perfect jobs for both Andrew & Harry, they both can get their military commissions turned back on. Get pay & benefits and do something useful and necessary as royal governors. (The UK apparently intends to keep hanging onto these bumps in the ocean, so by definition they ate useful and necessary!)
Just bring a dose of realpolitik to the discussion, those tiny bumps in the ocean, have a 200 mile economic exclusive zone around them. The formula for the area of a circle is πr2 which translates to for mineral, oil, and gas righty to 125,000 square miles of resources. Only a foolish country would give that up.