Thanks Jim.
It is platinum. I have both and prefer the platinum.
I'm just trying to narrow down this colour cast. Christopher James in The Book of Alternative Processes says that distilled water must be used as the initial water bath (with citric acid) because " there might be chlorine in the water supply. . . and this is a powerful oxidant.If the silver oxidizes during this stage, highlights will often turn a light coffee tan."
I will try the distilled and see if that makes a difference.
Of course it also could be that the ferric iron is not all being removed in the clearing and wash. I am clearing in three separate water baths (with citric acid) and then washing for a few minutes in running water, for a total of around 15 minutes. Also, I am doing two coats of sensitizer, which can also be problematic but I find necessary for good dmax.

david