Military wrap spring problem with 60 series hitting the mount

Hi All
Happy New Year to everyone.

I have an old 60 series which has had ARB springs fitted about 7 years ago, they are the heavy duty version with the opptional extra leaf added.
they have performed well and I have been very happy with them. but last year I had a "clunk" sound develop when the suspension was compressed on dirt tracks and even at times on rough surface bitumen it can be heard.
I looked everywhere and systematically removed sway bar links and shockers to eliminate the noise but in the end found it was coming from the rear of the front springs where the military wrap is hitting the spring hanger from the chassis.
I replaced the bushes as I though this must be the issue, but they were pretty good any how.
these springs also have nylon anti rattle bit over the steel sections that hols the spring pack aligned, and I replaced these also.
while apart I even buffed off the corner of the military wrap as this is where it was hitting as the hanger comes down on an angle (I looked at an old HJ47 and the hangers on this are more square and this problem would not occur in that case)
I have discussed with ARB and even though they helpful, they say they hadn't had this issue before and couldn't offer a solution.
has anyone had this issue ?
does any one have any ideas to help solve this problem?

Regards
Dingo