jkn wrote:

I now think that the rods were OK, but that the window had dropped
slightly.

was the glass "packed" correctly before?

am now looking for tips on how to do a final refit when the tape arrives.

sorry, have only done internal glazed ones (thankfully).

Would
the panel suggest putting packing pieces in first, then putting the glazing in,
or (say) put the glazing in, then slide it around to fit the packing pieces?

I put bottom ones in first, then panel, then top/side diagonal packers,
finally squeezed in an extra 1mm to make them tight if needed.