Hi Toni,
I am afraid I am not an engineer and would not know how to test the resistance or where to find the location. I wondered if it might be the water pump since I understand this boiler has two; one for the CH and another for the Hot Wate Supply.
My boiler central heating runs just fine. When we run the hot water with or without the heating on, the water gets hot then the boiler turns off. Only by waiting some 15 mins can I reset the button at the top of the boiler to get it going. I suspect the water is too hot and the cut out is acting...