Well, the resin mix was a disaster. It set after 24 Hrs with a 10mm hard crust but was still soft in the middle. I didn't want to increase the amount of resin in the mix as it looses that inert feel when you rap it, so I scooped it all out and cleaned up the top plate and mould box with Acetone. I will revert to a tried and tested technique and cast it in concrete. Coated the already Polyester coated underside with PVA and let it dry. Gave it a second coat of PVA and while this was still wet poured and tamped the concrete. The concrete was made up of 3 parts Horticultural grit (4 to 5mm), 2 parts sharp sand to 1 cement, I kept the mixture fairly dry. I also mixed up some mortar using just the sharp sand, this was pushed into the small spaces, corners etc where the gravel would not fit, it was all tamped down together. PVA was also added to the metering water of the mortar and concrete.