Wild Wednesday: Bertie and Beatrice?

As I mentioned a few weeks ago, we have a seagull's nest on one of our chimneys.

Two weeks ago, we spotted one of the chicks wandering around the garden. He was still some way from being able so fly, so we're not sure how he got down from the nest safely (it's 70+ feet up!) and he's been a bit of a worry to his poor parents, who have been swooping around trying to look after him and keep him on the straight and narrow as he repeatedly wanders off towards the woods (with foxes etc.). We call him Bertie.

His more sensible sibling (obviously a girl - Beatrice :) has stayed in the nest, and today I got the good old 600mm mirror lens out to get a proper look at her. After 10 minutes she obligingly popped her head up and wandered out from between the chimney pots...then so did a second chick!!

I'm not sure what's going on here. Is this Beatrice and the previously unsuspected third sibling? (Bobby?) Or has Bertie finally got to grips with his wings (he was fluttering about a foot off the ground at one point yesterday!) and flown back up to the nest? Either way - great to see the family doing well :)