It is quite normal for these birds to come back occasionally to the breeding colonies in winter (sometimes from about late November onwards) but then to go back out to sea again for some time before returning to the cliffs. This sort of movement happens throughout the winter period. We suspect it is probably the older (breeding age) birds re-acquainting themselves periodically with their nesting ledges during the winter period.
Hopefully they have been able to find shelter and won't end up starving on our beaches.