Good point John. We can certainly do a mass mail to the membership and see what happens. The forum has had 540+ members access it since signing up to ICB, but actually, 699 people registered, the balance having never accessed the forum (and the only real reason to register is for forum access).
During the move we will transfer everyone who has ever accessed the forum part at a minimum, but there is an option to drop the accounts (spring cleaning if you like) of those registered users who never posted or visited the site within the last 12 months, for example. A mail shot would be a good idea to see if we can reanimate some of those registered users.