This route has exactly one certifying stage
Australia joined the Hague Convention in 1995, and that single fact settles the shape of the whole job. An apostille for Australia is the correct and sufficient certificate, so document legalisation for Australia does not run through a consular desk at all. One office, one fee, one mark on the paper.
Knowing the count of stages is what lets you judge progress. When a route has one certifying step, the file is either waiting for it or past it, and there is no middle state to worry about. Long chains breed anxiety because people cannot tell which desk holds the paper; here there is only ever one.
What a finished file looks like in your hands
You get your paper back with a separate certificate fastened to it, completed and sealed by the office that issued it. The pair travels on together as one item. That is the whole deliverable, and an apostille issued in Coventry for use in Australia produces nothing else — no card, no register entry you can look up, no confirmation letter to file alongside it.
So the test is physical rather than administrative. Look at the sheet you are about to hand over and ask whether the certificate is on that sheet. If it is attached to a different copy sitting in a drawer, the file in your hand is not finished, however much has been paid.
Signals that look like progress and are not
Three things get mistaken for completion. A sealed copy from the register office, which only makes the copy official. A payment receipt, which records money leaving rather than work arriving. And a scan of the finished pair, which shows the picture of a certificate without being one. Each is worth keeping and none of them closes the job.
The opposite mistake also costs weeks. Some people finish the British stage and then go hunting for an Australian stamp to add on top, because that is how they remember an older process working. There is no such stamp to find on this corridor, and looking for it delays a file that was already complete.
Plan the count before you start
A finished sheet is usually surrendered rather than shown, so the practical question is how many separate bodies will end up keeping one. What you need for an apostille from United Kingdom to Australia is one certified copy for each of them, because the certificate binds to a single physical sheet and cannot be spread across others later.
Ordering several certified copies together at Cheylesmore Manor House costs one visit; deciding you needed them afterwards costs the whole route again, fee included. Both waits on this corridor — the register office printing, and the Legalisation Office turning the sheet around by post — vary with how busy each is, so no exact date can be promised for either.