Confidence: It's likely to be this, but I can't be certain.
Notes: Basal three postpetiolar tergites almost entirely yellow, rest of gaster almost entirely black, giving the appearance of a single broad yellow band. Definitely not Amblyteles armatorius which has a different colour pattern: has a series of narrow yellow apical bands in the female, e.g. http://www.ispot.org.uk/node/86404 or two irregular yellow bands in the male, e.g. http://www.ispot.org.uk/node/224563.