Just to add, we don't know the hot end of a soldering iron from the cold end, that's why I'm trying to gather information from appliance engineers on here.
There is no quick fix anymore. The old machine is dead. It was dead before he told us we needed a motor. When he fitted the new motor and then discovered it still wasn't working due to the failed triac, he said boards/control module replacements are too expensive to bother with, and we should give up on the machine.
We've had to order a new washer. The only way we can cut our losses even a little is if we gather enough opinion suggesting he should have spotted or detected the knackered triac when he came out and told us we needed a new motor - and get him to refund the cost of that motor - which unused, he cam come and take away to potentially use on a future job.