Electrolux ESL6115 keeps filling with water

Hi there.

I have a Electrolux ESL 6115 fitted dishwasher in the property that we let out last year.
When we bought the property the dishwasher was in place, new and unused.
The tenant a while back complained of a leak from this dishwasher, where it was eventually filling in the inside, with fresh water and leaking out onto the kitchen floor.

Bizarrely its at this point we found out that when he first viewed the property he thought it was a washing machine (!?!), so had not used it as he lived on his own and had no need for the dishwasher.

We live over 100miles away so have to rely on the management company to get a plumber in. As the guy only wanted a washing machine, the plumber capped off the water supply and problem went away.
We have a new tenant moving in, so need it resolved.
As the machine has not been used, but sat there under mains water pressure unused, I assumed an inlet valve had let go.
Is this assumption correct? Would this be the likely cause???

If so am I looking of a solenoid inlet valve, and are these easy to fit?
Or is it likely something else.

Thanks