What can I add that hasn't already been said? You are all right. Maybe just that you should do it for yourself, above all. "Do it for England, do it for love...Do it for us, do it for goodness sake...Do it for all the times, we wished we had...Do what you want, just how you like...Nobody has to know...." Wonderful!
I feel like Tidal captures Imogen's lifetime musical journey, from the beginning to thus far in her life.[ I completely agree! It's like all the tricks and styles she has picked up along the way, she has put into this song.
A little bit of IMegaphone, Details (from Frou Frou), Speak for Yourself, and Ellipse can be found in this song if you listen close enough. This track holds Ellipse together. I love the whole album, but this track is what keeps it all rooted. I feel like Tidal captures Imogen's lifetime musical journey, from the beginning to thus far in her life.
On the contrary, I like how the song ended. It was unexpected and not a poor rock-wannabe piece, imo. 
The ending MAKES the song, it's innovative and interesting, only Imogen could compose a song like this.
Before electric light, you paddled through the soup of darkness as a crocodile...god I love this song so much. This is the best one off the album, imo. Canvas is a close second, but this one captivated me from first listen.