Pete, your plans look great
There are 2 changes I would recommend though (from my trials and errors

)
If you're putting in a concrete base anyway, make a small foundantion and build a couple of rows of concrete blocks at the base of the stable walls, put the wood above this. Wood could/will be chewed and pushed out by the weight of a fully grown pig lying against it - block won't.
Also, try to allow enough height for you to go into the stables without having to bend over - this will make cleaning, changing bedding or assisting with farrowing
much easier (or you could keep the roof low and have some sort of hinge to allow it to open for that purpose) There's nothing worse than having a sore back after a couple of hours of farrowing or hitting your head repeatedly when cleaning

Oh and remember your drainage and slopes
Mwncigirl - we use an old cow shed which is divided up into pens of rougly 6ft x 18ft with seperate bed, eating and dunging areas. If I was starting from scratch, without buildings, I'd be looking to make a large shed (concrete, metal, anything really) with a solid base and bolt fixings to the floor to allow you to put posts in to hang gates, or construct pens but only as and when needed. This would give you a really flexible space and you could alter the layout for farrowing, overwintering, or at some point in the future if you start to think about goats, sheep, cows etc It'll also be invaluable storage space/indoor BBQ venue when not being used for livestock
HTH
Karen