Alan,
Classy pop and as Alan says your WIP sounds finished to me, and I know you'll hone it even more.you talented blighter!
Great chorus, really like the Do. Do, Do's ( I guess they may be a placeholder but it worked for me ) and the variation on the middle 8.
Apart from putting a snare on the later choruses the only other suggestion i could make is perhaps up could have a bigger gap and lift the key a couple of semitones after the middle 8 at 3.10 to build tension? Its know a bit hackneyed but it can work...
Neil