Took about 26 hours total, so a full weekend and couple of evenings painting!
I made a couple of changes - things are typically in cm/mm here in the UK, and couldn't find 1" planks anywhere (so used 18mm planks, and 44mm square timber). Also used 18mm MDF for the sides and back, as it was a bit expensive to use nice wood, and no point anyway if it's being painted.
Very pleased with the result, they look great.
stain - B&Q varnish - mixture of "light oak" and "dark oak".
varnish - Colours Quick Dry Clear Satin Floor Varnish (3 coats)