Finally my tanks arrived, there are two tanks both 170ltr capacity, one for gray water and one for black.
I started work on them by fitting the valve system for emptying the tanks, the tanks arrived with inspection hatches already fitted buy I didn't like the quality of them so I will change them for the better Henderson hatches.
The electric valve you see fitted to the rear of the gray water tank is the "don't store it in the tank" valve, for use when you can.
They will be fitted with level senders, an automatic wash out jet and an oxygenation system later.
Next job to make a frame to hold them and attach it to the chassis.