It's a long report, I've not read every word. I see the first maintenance engineer gave advice and based on that the crew made the decision to continue. By the time ME2 was involved VHHH was clearly the only possibility. I still haven't found any discussion - just a one liner "reasonable". Maybe no more needs to be said.
Might be long, but this statement makes some pretty large assumptions:
I'm curious as to the lack of any consideration or discussion in the report of the decision (however right or wrong) to have continued the flight to destination with faults showing on engines and one engine ineffective relatively early in the flight.
Your questions are answered in the report. The engines where not "ineffective". They were both producing cruise thrust and the crew carried out several tests to ensure they were functioning normally. When they carried out the step descent, the engines responded normally as well. Being a fuel contamination problem, I think this sort of issue grew in severity as the flight progressed, and became a real problem only upon arrival at their TOD.
And the decision to continue was talked about in several parts of the report, and deemed completely safe and appropriate. That is what led me to question your insinuation that it was not.
You an I can sit here with the knowledge of "fuel contamination blockage caused by SAP spheres", but they did not have that knowledge at the time. All they had where some ECAM messages for which they followed their QRH and discussed with engineering for further insight.