.. heard recently from a BA chappie that the 747 and 777 crews are being rostered an extra day in the sim just for hand flying exercises
Not true. Recency for FO's in BA means just sitting in the seat for a sector once a month and a landing once every three months. For Captains, it's a monthly landing. If this is likely to be compromised due leave/sickness etc, then a quick visit to the sim for a recency ride is planned for an hour or so, but certainly there is no "day in the sim hand flying".
Rod