Siemens SE26T251GB/04 – Not filling

I’m a newbie, fairly competent DIYer but no white goods expertise or electrical/plumbing qualifications. Thanks in advance for any help you’re able to give (I’m one step away from replacing the offending appliance)!

Siemens SE26T251GB/04. Functioning perfectly for 10 years till last week. Set it off on usual program which it went through to completion, but hadn’t washed at all. Soap dispenser open but tablet intact. No residual water or leakage, No error messages

Checked Inlet hose filter – clean but cleaned it anyway, drain filter ditto. Ran it again, and seems to start normally with drain pump for a short cycle, then progressed with normal cycle but no sound of water filling or circulating. Opened the door at various times and almost no water – some “dribbling” from rotory arm and main inlets but not enough to do any work. Cycle ran to completion, dry chamber and indicator that it had finished properly (same later with pre-rinse), again no error codes.

I was hoping it might be something simple like an inlet valve or blocked hose – forgive my ignorance if that is nonsense – and had a friend of a friend who is a service engineer look at it. He said that the drain pump and the filler (I may be misquoting) were operating at the same time so the main chamber never got to fill properly. He couldn’t detect any blockage and said the problem was highly likely to be the control unit and given the cost of a replacement unit and it’s fitting (?and programming) and the age of the dishwasher, it might be better to replace the whole thing.

I’m sure he’s probably right, but before I trash what was until a week ago a brilliant piece of kit, I wondered if anyone had any alternative (or indeed confirmatory) thoughts.

Cheers

p.s. quite hard water, 21.9 Clarke