The RSPB Fulmar page/ sand martins in Norfolk cliffs

hi,

I wanted to know when eggs are laid and some info about the fledglings. The RSPB  Fulmar page sadly is rather sparse on these topics. Although I see fulmars regularly on our North Norfolk cliffs, one can[t actually see any eggs or young. Any info would be appreciated.

Also: our local sand martin nesting cliff fell down late last summer whilst some martins were still about, leaving only about 30 or so viable nest entrances (there were more than three times as many before). A week ago I saw about 8 martins flying around the remaining cliff wall, entering some nest sites, and seemingly fighting over them -???-   I haven't seen them again. Is it likely they abandon the site, and would they actually fight each other for the sites?  I heard that nests disappearing 'isn't a big deal' as martins would happily dig new holes; however, I have never seen this, and it seems a heck of a job for a small bill like theirs to dig a tunnel entrance.

many thanks for any information on this!