Over here the UV gets to those boots in a few weeks. To the best of my knowledge they aren't available as a separate part are they? It would mean replacing the loom?
The ones on my Griso died eight years ago, never done anything about it. The Turdio doesn't have them because at some time in its wretched life a PO fitted a Power Corruptor so the injector plugs and boots have all been hacked up and are now wrapped in a gazzillion miles of insulation tape! I love it, it just adds to its turdiness!

Pete