Apologies Robin,
We are not talking about the same person,mine appeared much later in the 1400's,he was a 2nd cousin to Owain Glynfyfrdwy[Owain Glendower] and fought alongside him in the uprising.
However I might have something else which could help.Looking through my records I came across Kydivor ap Dinwal.He appears roughly around the dates you mention.He was married to Katherine,a
daughter of Lord Rys,Prince of South Wales,who was commissioned by King Henry 1,in 1169,to be Chief Justice of that country [DwnnI.28,37,65,80,227].
Kydivor ap Dinwal took by escalade,for his Father-in-law the Castle of Cardigan.In gratitude,Lord Rys
granted him Castle Howell and other lands in the Parish of Llandyssill,also a Grant of Arms,viz:-Sable,a
spear-head embrued between three scaling-ladders,argent;on a chief gules a castle tripple turreted of the second.There is a comment by Meyrick in a note to Dwnn1,227 that this coat is far too elaborate for the time and that it was in all likely-hood used by Kydivor's descendants.
Hope this helps,I came across it as I'm researching the connection between my Cadwgan and the Lord Rys.
David [brawdhoudini]