Whirlpool AWZ612 washer/dryer help

Hi was looking for help in fixing a fault on my Whirlpool washer/Dryer.
Machine is 3 yrs old and after a year developed a fault where the re-settable thermostat (probably not its correct name) would trip being used as a dryer. Resetting it by pushing in the red button would clear the fault for a few drying cycles. Eventually had an engineer attend who put the fault down to a build up of fluff in the big see through tank on left hand side of machine if looking at it from the rear.

Fault now occurring regularly (after fix 18months ago) but now the clothes seem to be really cold when machine is used as washer and machine won’t heat up when used as dryer. I’ve decided this time to try to fix the fault myself to save a bit of cash for Santa.

My thoughts:
Possible faulty heating element on washing machine
Possible faulty heating element on dryer
Possible faulty thermostats/sensors on either

Findings so far:
Plastic see through tank partially blocked with fluff (not bad but cleared and refitted)
Resettable thermostat resistance 0.6ohms with red button pressed in
Resistance of heating element on dryer 56ohms and 57ohms
Resistance of heating element on washer 27ohms
Dryer heating element also has fair amount of fluff around it. Now cleared
Voltage at heating element on washer 240v and 0v at times

I’ve quickly put the machine on for a 30 degree wash just to check all the bits I’ve took off have been put back on correctly. Usually the door heats up a bit but it’s still cold. Currently got a 90 degree cycle on. 240v at heating element but still the door feels cold(after 10mins through cycle) just re-checked voltage at heating element now 0v. Surely this would be 240v for a while to keep water at temperature?

My question is:
Would a faulty heating element cause the problems I’ve mentioned with the washer and if so is the thermostat situated in the heating element fitting thus renewing the element would renew the thermostat also?

No further testing on the dryer but would the previously mentioned problems be caused by a faulty thermostat? It looks as though there are a few thermostats and sensors dotted around the machine?

Thanks in advance for any assistance and apologies for the novel and poetic description of components.