Thanks everyone.
The rubber particles have not dissolved and are the larger bits are easily removed through draining the tank by way of the lower sample/drain valve.
As an engineer I'm confident that the 0.5 micron filters will keep the fuel at the nozzle contaminant free but our outside helicopter management company issued an incident report condemning the fuel imediately.. Frustrating as the bulk tanks were only just filled up from near empty two weeks ago at a cost is 22k.
I think In cases like this it's probably best to err on the side of safety and, based on the fact that an incident report has been issued, it's pretty much been taken out out of my hands...
Anyone need 8000ltrs of Jet A1?
Thanks again for the advice, great to draw on such a broad spectrum of experience...
Kind regards
Simon