No, I checked each filter with the mask and they are parfocal.
Eric has kindly lent me a set of Astronomik filters so I can remove filters from the problem list. But not tonight, a storm is brewing out there
The huge improvement with a pollution filter in the chain has me baffled.
[edit]
It looks like it's a combination of light pollution and optics. Got the first image from the WO70 with the astronomik filters and the second from the tak, both with the idas filter.