Typically I strike gold just after I posted:
Thanks and I hope I didn't waste anyone's time
J
.....................Solution..........................
WITH
MEMBER
[Measures].[ACCOUNT_CODE]
AS
'[ACCOUNT.H1].properties("PROP")'
SELECT
{[Measures].[ACCOUNT_CODE]}
ON AXIS(0),
{FILTER (DESCENDANTS ({[ACCOUNT.H1].[LEV10]}),[ACCOUNT.H1].properties("PROP") <> "N")}
ON AXIS(1)
FROM
[CUBE]