Yellowed dulux brilliant white paint

[Coaster]

I'm one of the victims of dulux's paint that yellowed within a month of painting in 2010.
That paint is still on as i was too fed up to take it off and do again.
I contacted dulux who only gave me vouchers.
Before i repaint, has anyone just sanded the effected paint and painted over it, or should i strip it off incase it affects the new paint?

Thanks in advance

 

[Coaster]

Btw, if i use the water based paint, will i have to strip the oil based gloss off first?

 

[ic1927]

No need to strip it off, just de-grease with meths, sand down and apply a bridging coat like acrylic primer/undercoat, then apply your water based finishing coats.

 

[Robbie uk]

Ideally you need an adhesion primer like Zinsser before the water based topcoat goes on. Sand everything well first.