SureColor P600 Color cast

My P600 has suddenly started printing with a slight brown cast, especially noticeable in the blacks and greys.

I have tried replacing all the black / grey cartridges (OEM) but no joy. I printed a BW test page using color and the same cast appeared. I printed the same image using the Advanced BW setting and it was fine, so I know it was not the inks.

My suspicions is that it must be a recent firmware upgrade. Anyone have any comment on this?

Also, anyone know where I can get the Epson .icc profiles from for all their papers (I use Traditional Photo Paper aka Exhibition Fibre). Cannot find them on Epson site

BTW Windows 10 64-bit OS