Hi Stu
Britannia no longer offer split base winter contracts so this is no opportunity for crew to work out of say MAN or LGW just for the winter. You could do the summer at NCL and request to transfer to LGW and then you may be offered a perm contract at LGW. This year no one was offered perm contracts at NCL and they have 4th year rejoiners waiting.........
Good luck at NCL - it is a great base and the crew are superb!