Lamona / Beko dishwasher faulty

This one I think is weird – it does the pre-wash fine, it fills n washes good then it empties and fills again but then just sits there – silent – then fills up a little more, then silent. After a while it fills again then starts to leak into the base and out of the sides!!
Sometimes on different settings it works ok though. The machine does heat and the motor turns ok on the prewash but no on the main wash it would appear as it just sits there with water in it, slowly getting deeper.
I do get some odd problems. Any ideas please??