Halliday & Matthiessen (2014: 124):
A structure that can look superficially like Theme predication, but is not, is that involving postposition, where one nominal element of the clause – typically the Subject, though not always — is delayed to the end and the appropriate pronoun is inserted as a substitute in its original slot. This may be a nominal group, as in:
they don’t make sense, these instructions
shall I hang it above the door, your Chinese painting?
in some places they’ve become quite tame, the wombats
Here the Theme is, as usual, the item(s) in first position: they, shall + I, in some places; while the postposed nominal functions as Afterthought, realised prosodically by a second, minor tonic with tone 3:
// 1 ^ they / don’t make / sense these in// 3 structions //