As posted after complaining to eBay I got a full PayPal refund within two hours and a message from the trader that there was no need to return the faulty power supply.
Happy to report and I think it’s a fair and just outcome after all the hassle that I have been able to repair the faulty power supply that arrived DOA.

Just finished replacing the faulty bits with new components I got from Jaycar this morning.- about $10 bucks. It’s working…yay.

Testing with a 12V LED stick that is pulling 390mA. Have to quit now cos there are other jobs on the list, back later to have another play. Stay tuned ..