Thanks for all the advice. It seems my chassis has been done in the past with clear waxoyl, and I now suspect the wood has also been covered with it. So I think I will continue with the clear waxoyl (especially as I still have a load of it).
David Morgan Plus 4 2005 Jaguar XJ8 1999 LR 110 Station Wagon 2008 Volvo V90 D4 2017