The current 45 day extension is due to end at the end of this month, but I have read many articles suggesting the 45 days will be continued. (Australian.) 

But so far I have not seen any official confirmation.

Have I missed something?

No

What you call an "on arrival visa" or "extension" is actually a "visa exemption" which means entering Thailand without a visa. A "visa" is usually issued by an embassy/consulate outside Thailand, though there are special cases where an immigration office in Thailand can issue one. The word "extension" refers to having your existing permission to stay in Thailand extended at an immigration office.

 

Nobody can yet say for sure whether the current 45-day permission to stay from a visa exemption will persist after March 31st but, more likely than not, we will be back to 30 days.

Thank you both for your replies.

Kermit