Complete Peerage of England Scotland Ireland Great Britain and the United Kingdom
(h) Called in NGR. lady of the manors of Horton near Canterbury and Bewsfield (otherwise Whitfield) near Dover. These appear in her Inq.p.m. Hasted says she was daughter of Guncelin (Joscelin) de Badlesmere, who gave these manors with her in free marriage to John de Northwode. No deed of such gift has been found, but John was said to hold 10 marks rents in Harrietsham of the gift of Guncelin. Her age would make it likely that Joan was sister, not daughter, of Guncelin.
The cited information was sourced from Book published by Sutton Publishing Ltd in 2000 (Ref: Page: IX:754-5, also note (h)) The author/originator was G. E Cokayne.