Merci beaucoup to Marc, Steven, and Dominique,
Sorry folks. I was stubbornly stuck in my journalist’s mistakes; both his wrong spelling and mistaken context. Thanks to Steven I finally did what I should have done in the first place and googled it to find that Regent’s ‘Marquis Peu-a-peu’ nickname for Leopold was well known and not some little known bit that my hero had picked up. So, Leopold was a fellow who did things ‘little by little’, bit by bit’ or by 'degrees‘ or ‘gradual’. My journalist did called him ’cautious’.