Thank you all
I cut my own patterns and rather than go for fashion or tradition I go for comfort and practicality.
This explains the buttonless "grandad" collar - it works but is comfortable without the button usually found on the stand - the loose body fit but tighter sleeves, the low but huge pockets - easy to access and lots of storage - and the half opening front -more wind resistance but lots of ventilation if I need it.
The fabric is "downproof" and meant for pillowcase and duvet linings but is comfortable next to the skin and pretty wind resistant.
I have made 2 shirts from this fabric and a tarp ... the tarp was proofed with Fabsil and has done me proud so far