What's the best way to proceed ? Carry on and hope for the best, or
somehow strip off the Ronseal preservative and start again ?
It sounds like the stuff that's half stain and half varnish. I painted over
it on somebody's front door a couple of years back. Looks okay but chips
easily.
Paint stripper and wire wool would be my choice, followed by a coat of 2
part wood hardener. Paint goes on like a dream once you've firmed up the
surface