Just walked back home from work and had a Canada Goose and a Greylag Goose fly over the house (outside the square) and westwards towards the Great Pond on Epsom Common where they roost. Which puts them in TQ1960 airspace. I watched them flying through the square and, hey presto, I'm over 300 just like that!
300 - Greylag Goose - 1 over Stamford Green airspace
301 - Canada Goose - 1 over Stamford Green airspace