Yes very good point Pierre… that is a much simpler way of analysing the tune.
Seeing your analysis makes mine look very convoluted… I need to work on my numeric analysis!
@niall - I agree with Pierre’s numeric analysis here:
That makes much more sense to me now with the F Major in bar 5 being the modulation to the IV which is a very common cadence found in jazz standards.
I made the mistake of analysing the tune in relation to the starting chord when in fact it is starting on the relative minor which is A Minor in the key of C Major.
There are parts of the form that are in A Minor, such as the B-7b5 / E7alt, but as you say @Pierrot - the overall ‘mood’ of the tune is joyful and happy sounding which is a strong indicator that the tune is written in a major key.
As you correctly point out Pierre, we should analyse the tune based on where the harmony ends, and that final point of resolution, which is C Major.