WHIRLPOOL APPARENT FILTER BLOCKAGE

We have just acquired (with house move) a Whirlpool dishwasher.
I THINK that the model number is ADG5720FD – I say ‘think’, because the model is built in and the documentation doesn’t (really – I’ve checked) give a model number at all; as we live in France, it might be a French-specific model number.
The FAULT is that it fails to draw in water and so each cycle stops very quickly and the error light flashes 8 times which, according to the booklet, indicates blocked filters.
We have:
– taken out and cleaned thoroughly (and they did need it) all the filters within the machine, but to no avail;
– checked the water drainage hose and the drainaway (sorry if these are not the right terms) and neither is blocked: if we put a bowl of water into the machine, it voids that perfectly and the water drains away;
– checked the water supply which, from the inlet tap to the machine, is fine.
Neither of us is very technically savvy, but we wondered whether there might be anything else we could try, before calling in a professional (we live absolutely in the middle of nowhere and the firm likely to come out have unfortunately been both very expensive and not very efficient in the past)?
I do appreciate anyone who takes the time to read this and, even more, any advice; if there is any other information which I could give to help, please let me know.
Thank you
Pabster
79120 La Fontaine
France