Agreed, so let's look at the facts from this little episode:
1 Oct 2015
- TCT seen discussing something with A N Other pilot with a chart at the back of G-JACS -FACT
- Ewald seen helping prepare this second aircraft (G-JACS) - FACT
- TCT departs Farnborough solo - FACT
- TCT lands at Merville for a "pit-stop" - FACT
- TCT flies on to Charleville for an ONS - FACT
9 Jan 2016 TCT
and Ewald land at Sydney Airport - FACT
Somewhere between these two dates she picked up her passenger/co-pilot/navigator/engineer/radio operator
*Delete as applicable. - FACT
Speculation:
I suggest it will be nearer 1 Oct 2015 than 9 Jan 2016.
Given the range of the Stearman and TCT's unquestionable aviating skills at following a magenta (almost straight) line why the stop at Merville? Why not just push on to Charleville.
A little more digging will soon turn the speculation into fact too.