Neff Dishwasher not heating 9 months after heat pump replacement

Hi,
Last summer I replaced the heat pump on my Neff Dishwasher – S51E50XOGB with an updated pump and wiring harness:

00654575 Dishwasher Heat Motor Kit
https://shop.ukwhitegoods.co.uk/654575-dishwasher-heat-motor-kit

Since then it’s worked fine until recently when a couple of things happened. Firstly, it started tripping out the house fusebox RCD part way into the cycle – I expect this was heating related as water pumped fine. Then the tripping out stopped and the dishwasher appeared to be operating correctly until I realised that it wasn’t heating the water.

I’ve opened it up to check the pump and there’s no obvious loose wires, connectors and no significant leaked water present in the base.

I’m unsure how to test what the issue is, if the heat pump has gone faulty then I’d expect to be able to relate it under warranty but don’t know how I can test whether this is the issue or the problem lies elsewhere. I was expecting to be able to use a multimeter to check for continuity on the heating element but don’t know which of the connectors is for heat and pump and other functions. Also, what should I be testing for??
Should I also be checking the control panel?

Any help would be greatly appreciated.
Thanks