two possible sources for additional recordings would be Brendan O'Duill and Peter Hunt who recorded the Gael-Linn Flea Cheoil album. There were 17 cuts on the album and three of them were the Grehan Sisters with Fergus Cahill. No Other artist was represented on more than one cut. If they made that much of an impression, it's possible more of their music (if there was any more) was recorded.

Also, at the same Flea in Clones in 1964, Peter Kennedy and Pete Seeger were recording for Folktrax, an album that was later released as FTX -172, "The Fox Chase" This info is from Folktrax' website: "Tracks #7-13 recorded by Peter Kennedy and Pete Seeger at the Fladh Cheoil, Clones, Co. Monaghan, 18th. May, 1964. For the last two tracks, #12 and #13, Felix is joined by all the other Uillean pipers who were performing at the Fladh: Leo Rowsome, Sean Seery, Pat McNulty, Dan Doherty & Seamus Dowling.

Edited by Peter Kennedy and first published by Folktrax 1975."

Sean Seery also appears on one cut of the Flea Cheoil recording and Felix Doran's cut is not one of those available on the Folktrax recording, so they may not have been recording at the same locations during the Fleadh, but it is remotely possible that Kennedy and Seeger recorded something by the Grehan SIsters, maybe Bernie's memory could be jogged about that, though getting the material from Peter Kennedy might be an impossible task. Folktrax never released any recordings of the Grehan sisters, but they may have recorded them.