I took about 6 weeks off weaving while youngest son finished high school and we went on holiday, then it was Christmas… I got back into it yesterday and today managed to finish the first half of the fabric.
I went back through my notes and figured out how far I needed to weave before beginning the blue plain weave border.
When I started the weaving, I had made an extra warp thread that was not threaded through the heddles or the reed. I had marked this thread as in the diagram above. I began weaving the header at 180cm and the blue plain weave border at about 177.5cm. 0cm is halfway along the yarn, 8cm gives me the space to do some kind of warp protector to prevent the fabric from coming undone. I finished weaving the variegated yarn 5cm before the 8cm mark and wove the blue plain weave edge. After 5cm of this, I hemstitched the end.
Hem-stitching (going from R-L) in progress 
Hem-stitching completed
I have used 4 full balls of plain blue yarn (includes the warp threads) and 2 full skeins of variegated yarn. 2 unused balls/skeins plus almost a full ball of each colour remain.