Hello Guy H, grip looks good to me. These I have seen did look more white or a yellowing white. Yours does look really more in the directon of soft yellow but nevertheless I like it very much. I assume that you have disambled the dagger (I do not recommend this!) or have other proof for a painted wooden grip as for me -only from the pics- it does look more like a milkstone grip with the characteristic lot of very small cracks? It is a WKC dagger?
I have seen several late army daggers with wooden grips, all painted white, some heavily chipped showing much of the woodcoloured base material. I have not seen this combination of Pack scabbard and WKC type 4 fittings before.