John

I fully accept your criticism as there is no sign of the gutteral termination to Creeagh.

However I have been working on another name element which might fit better.
This is the Old Irish Rig (variants Rigidh & Riged) which meant the fore-arm (see e-dil, the on-line Old Irish Dictionary). In Modern Manx this has evolved into Roih - this means arm (see Faragher p. 40, Cregeen p. 156)

The loss of the terminal "g" and the change to "ee" is precisely paralelled by the Old Irish rig meaning King which became Ree in Manx.

Going by e-dil, the genetive singular of Rig in Old Irish was Rigead and the Dative singular was Rigidg.

The sound changes are expert territory, but it is possible that Mac+Rigead could give Mac Crere as Balla+deorad gave Ballajora

I am only getting into the extent of the places using Roih, but I will be looking at places like Cooil Roi, Glan Roi, Slieau Ree . THese places could be an arm of land projecting, or might be reference to some kind of ridging. Anyway this is an alternative where the gutteral does not interfere.

Regards

Nigel