Knowe of Crustan

Can you call it a field visit when you have only viewed from the road with a high-powered digicamcorder. Answers please on a postcard ;-)
Approaching Birsay from Swannay not long past the Knowes of Lingro (possibly even along the same ridge, see vid.supra I think the term is) you see two small square wartime buildings on the hillside with a grassy hump between them and directly to their right a mound. This is the Knowe of Crustan. You can easily find a mound that seems to be another fragment of this as you scan along the horizon.