Mine is actually X1 coolant not XT1. I realised it when I dug the 5 ltr container out for my support ticket yesterday. I used XT1 in concentrate form before all this started and then bought the X1 direct from Mayhems as it was much cheaper buying in bulk. I have asked for the title to be changed.
I have had a great response from Ian with regards to my ticket at Mayhem's so far.
I've got great response from Ian as well, just the ticket system is not the best

Mine is the XT1, but the major problem is that I contacted them before and I was told that the residue was flux from the rads, so I spent money "solving" the problem as they advised me and now they are saying is a tube problem.
But again, so far they are providing a great support, lets see how it ends.