Splendide 2000 water mixer valve

On our model 2000, when we have the washing machine turned off, water still runs into the tub when on city water. I checked but see no water mixer valve so it must be behind the rear panel. Looks to be a bugger to get to.

I read where one poster said parts for the 2000 are no longer available from Splendide, so does anyone know where this part could be obtained? Of course I am assuming that the mixer is the problem!

Thanks

Wayne
01 Dynasty