On Thursday, 26 July 2018 11:38:32 UTC+1, Bert Coules wrote:
I keep coming back to the lazy-tongs, collapsible pole idea, though the
former would have to be strong and sturdy enough not only to support the
figure but to do so without swaying

two lazy-tongs, at right angles, should be sufficient, and buildable in meccano or dexion strip. Or Bilofix if you have any.

https://da.wikipedia.org/wiki/Bilofix

Or expandable garden trellis columns.

Owain