Thanks for all the good responses.

As Lance pointed out it sounds like the biggest problem is the fact that I'm
using KD poplar. Can it still be done or should I try to get some air-dried
poplar (poplar has become pretty scarce in Australia since the Redhead match
industry died out, especially air-dried).

Is it possible to somehow rejuvenate the lignin, soaking or steaming ?

I used the Barnes method from his spinet book, which suggested soaking for
48 hours(?), I soaked the wood for 3 days.

I think I will either steam or soak ( for a longer period) and then clamp to
the mould and dry it out over a barbecue with hot coals.

regards,
Andrew