installed new skirting boards a few years ago and all knots were treated with knot stop, but over time they have shown through the white gloss .. nows the time to redo the paint work , is there anything i can do to stop the knots showing through again ??

buy MDF skirts if you’re bothered about natural wood features…

I’ve always found Shellac/Knotting Compound to work, why not try another coat before repainting

you might have to sand back to get another coat of knotting solution to work. You could try a stain blocking paint?

Wear looser fitting clothing?

Try some aluminium paint, should do the job.