Thanks John.
To confirm then, the correct transformation would be:
(x, y, z, 1) * T
which is not the same as with NIFTI sform.

Unless I'm missing something, row-major or column-major order only specifies how the data is stored (how to convert from a list to a 2d matrix).  It does not imply anything about the meaning of the values in the matrix.  And I didn't see any indication that (m13, m14, m15) were the translation values.  So I really think this should be indicated in the documentation.  I suspect I'm not the only one that would have assumed the "wrong way" of making the transformation.

Thanks again for your prompt reply!
Cheers