With some more lateral thinking I've pretty much sorted it now.
It just relies upon setting up the threaded frames correctly.
Two text boxes threaded together, that are then threaded to the next pair, and so on. Once you get to the right-hand page, you can move the first box over to the right, and the second box to the left. This then creates the correct layout as per my post above, and needs no changes to the XML.
First box - anchored pic box inside (this is where the headshot goes), followed by paragraph return. Text thread this first box to the second...
Second box - anchored text box inside (this is where the biog text goes), followed by paragraph return. Text thread this second box to the next first...and so on...
But I can't figure out how to then make the data flow into the right-hand side with the different layout.
Can this be done easily?
Sort of. I did it myself for a projet and the solution stand in anchoring the frame inside a text frame. This text frame will use a paragraph style which justification is set to opposed to spline. Then the textframe is also anchored to the main xml flow. Don't forget to use object styles !
Eventually when the "modules" move from an odd page to an even and vice versa, the the pic frame will be moved from left to right or the opposite regarding the side of the parent page.
A bit tricky but that works definitively.
Wow, I didn't even realise that option was there. That's certainly a useful thing to remember. Thanks.
I can certainly see how it might be tricky to use. Can't quite understand how it would avoid the text in my example below.
This is the layout I've managed to cobble together, which seems to work. There are two main text frames that are linked together. Inside the first is the (grey) pic box. Inside the other is a text frame with the biog information. And inside THAT one, is a box for City and Twitter.
I my project I had also an achored frame containing the text which would have an opposite setting. Eventually both will go sideways.
Ah, of course. Genius.