Nigel,

Thanks very much for that analysis. However there are few, if any, more recent examples of McCrere being written as McCreagh - and if that was the original form it must have been in use some time (100 years +) before the earliest surviving written example of the name in 1490 (as McCrere) - for it to have evolved into the more convenient written form McCrere.

Still it is an attractive and plausible idea.

Thanks

John