Mutoh XpertJet 661 Varnish Blemishes

Hello Everyone.

I have a Mutoh XpertJet 661 UV printer and on every run when I print varnish there are spots or blemishes in the varnish. This is every run, day in day out, I cannot use the varnish it's that bad!
If lay out 12 items on the bed, every single one has blemishes.

I have uploaded some images below.

Is this likely to be caused by environmental factors such as dust, static or carpet fibres?
Could it be a problem with the print head or curing?

Thanks for reading, I am still new to UV printing and can't get over this hurdle.