Vektro cap extender/adaptor

My spa vac cap broke rendering the whole unit useless unless I fixed the cap on with sticky tape each time I wanted to use it. I tried various glues to fix the tabs required to locate the cap on the screw fitting, but it was always breaking and weak. I used a screw for a bit but even that wasn't ideal. I thought about re-printing an entire cap, but just creating an adaptor and taping the old cap onto this appeared to be a much better solution giving the leaf catching area larger with a much stronger fitting.