Barry,
Here in the States, many on this board who have had the same problem go to retail locations which sell aluminum tubing, and cut them to the length needed. Just be certain that the outside dimensions and the inside dimensions match those of original factory spreaders. Some on this board purchase tubing that have a slightly thicker outside dimension than the originals. I'm sure you could fnd aluminum tubing sources.
More important, once you solved the problem, you may find it easier to just remove the spreaders when de-rigging. It's much easier than trying to manipulate the mast so as to get the spreaders under the life lines.
After bending a few spreaders myself, I now just disattach them from the mast, but I also keep one on board as a just in case spare
Ray