Sod, ive put a tape measure against it and eyed it up and 610 looks about right. Dont know why ICS would list it as 550 then. Will take a look and see when I get hold of it, can probly find a mate to buy it and get the 590 or 650 and trim it.
Shame your having issues, Ive had a play with a few of the ICS L86/85s and theyve all been pretty decent.