Hi. Just joined in an attempt to identify a bird we've been hearing lately & can't figure out. For reference, we're in central(ish - Finsbury Park) London and our place backs onto a small, inaccessible, overgrown woodland area. We only noticed the call a couple of days ago and neither of us has heard it before. It's a slowish, measured series of four or five 'toots', similar to the the Greenwich Time Signal! The nearest we've found so far is the Great Spotted Woodpecker (♫ Great Spotted Woodpecker - song / call / voice / sound.), but it's definitely a deeper/'fuller' tone. We've been hearing it around about 10pm/11pm. Thanks.