Not a huge progress but I think I had better feed you a little more anyway ...
After lot of patience the back is flat enough to deal with.
I don't have a shooting board four feet long so I improvise one on the benchtop. That's a #6 Stanley sliding on a waxed laminex benchtop.
The centre joint is dirty to the core so I have to plane back to clean wood.
its nice putting the halves together like this because I can see how the two pieces are only a sawblade's width apart from the same plank. At least. i think i can see this.
I'll have to chalk fit the centre joint i think. The Stanley is good for getting a nice flat joint and the Veritas low angle bock plane will help me smooth any ripples.