Nice one, Tom. Everyone assumes Grubenhauser (can't do umlauts on here
) sit very low, but there is evidence of a variety of sizes and shapes, and based on the archaeology being just the post holes, the length of the posts (and the height of the building!) is open to interpretation.
It actually looks very much like the simple row buildings I've seen in the reconstructions at Yorvik (so it must be right!). It'll make a lovely addition to your table.
Oh, one thing - I can definitely build mine cheaper than £3.50. But then I am the LAF branch of Bodgitt and Scarper Construction Ltd