Tonight I managed to get the sleeves into the shirt in a satisfactory manner. Each sleeve has been inserted 3 times but I am finally happy with the result.
I struggled to get the sleeves in last time I made this shirt as well so there is an obvious issue with the alterations to the pattern which I need to address in future.
Anyway this was an idea from Jenni (YorkshireLass) on how to get the sleeves eased in. It is a strip of very thin knit, sewn to the seam allowance instead of gathering stitches which pulls the sleeve head nicely into shape and makes sewing it in easier. (see lower picture for how this works).
The shirt still needs buttonholes and buttons adding but its 11:30pm on a Friday night, so I will tackle that another day when I am fresh(er) .