Tom's Narnia Costume - drafting

Tom wants to be Peter, from Narnia, for World Book Day (March 2nd in the UK). I've bought all the fabric, have a pattern already (Simplicity 5520), which should be easily adaptable. I've just drafted the shoulder armour (no idea what the technical term for that is!) so tonight I'm going to attempt to sew it up... fingers crossed!
Here's what I have so far:

Needs a bit of re-jigging but it fits great!
I drafted using pictures I found on narniaweb
In particular, this one: