I have now heard from the Ulster Historical Foundation, who can do no more than confirm that Robert Marchbank was "awarded one spinning wheel for growing a quarter of an acre of flax in the civil parish of Kilcronaghan, Co. Londonderry." The covering letter makes it clear that tracing him any further is rather unlikely to be successful. Such records as there are make it seem that there were no longer any Marchbanks in Ireland by 1830. This has cost £15, which I will draw from the Family funds in my possession. Roger