Not on a yacht unless you belong to one of the few yacht clubs whose members are entitled to fly the blue ensign when they are on board.
Otherwise you'll have to get a British registered merchant vessel and have a crew whereof a number are retired RN officers ! [Wikipedia 'Blue Ensign']
Another red one ? Well, yes, i see why you'd prefer a blue one. And you could fly a defaced red ensign, which is classy, though not 'naval', if you belonged to The Royal Norfolk or one of the very few other yacht clubs entitled to it.



