Update Tuesday morning Australian EST.
ACW418 finally had confirmation on Monday that the application has been received by TfL and now with 'another department' for checking. It was posted by him on Saturday 10 days ago, 1st Class Recorded Delivery, since although they would accept a scan of the application from Dad via email, it still had to be posted
Dad leaves tonight and arrives on Wednesday morning at Heathrow. It looks as if the jobsworths have won, but should the Veteran's Oyster arrive whilst Dad is in the UK then ACW418 has said that he will get it to him.
It goes without saying that we are indebted to ACW for help in this saga; I think he has seen it as a challenge