Thanks Richard, it's really the work of my son Tim. He is trying to trace everything he can about the Barclay family in Scotland and one of the Dundemor properties was later held by the Barclays. He tells me that Waldin de Dundemor held Denmuir in Fife from David earl of Huntingdon and was the squire for John Bisset, and that Waldin's son Henry and Simon were also closely associated with John earl of Huntingdon and Chester. Waldin was descended from the de Warenne family and was possibly the illegitimate son of Muriel de Warenne of Wormegay. The three garbs of wheat in the Dundemore coat of arms are the same as those found in the arms of the earls of Chester, but the tinctures are changed (as would be expected). But scallops might mean something else like you suggested. Do you have a date for this seal?