Finally it's complete. There is no pattern for this it was just made up as I went along using cotton DK and I think a 3mm hook.
I worked the top parts first using a fan stitch, working towards the shoulder shaping as I went.
Then working downwards with the same fan stitch, the first row creates a circle, continued until desired length. Sew back and front together.
I used a pineapple style hem, chart which I found here, yes it was for a bag but works good as a hem too!
Finally single crochet 4 rounds, creating a button hole on round 3.