Cheers Nigel, with a figure this well made I couldn't go wrong, well not unless I tried very hard.
With the ultra matt I just started adding it to the paint and still.used water, then with just a pot of dirty water I didn't want to use to thin paint and being far too lazy to change it I started using the varnish to thin the paint. I'm not sure what the long term effect it will have is though, only time will tell.