I'm being a cheapskate as I have 12 doors to paint & thought I could use a cheaper alternative primer/undercoat with Farrow & Balls water based eggshell in Wimborne White. It isn't working. No matter what base I use, oil or water, the F&B eggshell doesn't stick to it. It just sort of 'shrinks' into streaky brush lines after a few minutes. I'm getting fed up with F&B eggshell now. Any ideas?