Well I found the culprit and there is the tool to fix it.
i still think it strange that it seemed to spontaneously fail after about a year.
the ring spanner didnít work as well as expected as it seemed to need the missing bit.
However it sped up the undoing as it is 12 point so could be repositioned quickly.
to gain access and remove the pipe it is wise to remove the vacuum pump oil feed and the vacuum pump brace as well as remove all the plastic bits and the inlet hose to ex egr

Regards PhilipA