I thought it might be 701, too. This one has the right name, though no ITI number:
http://www.scotweb.co.uk/tartan/Cler...-Ancient/50213

And it is apparently different from Clergy (Clark) 701
http://www.scotweb.co.uk/tartan/Clergy-Clark/55139

As well as being different from this similar pattern, Clergy Green (Strathmore) 6459
http://www.scotweb.co.uk/tartan/Cler...rathmore/55155

The plot thickens!