Thanks for posting. This exact assembly is no longer made, but you should be able to replace it with our 40-058 Lockset. Take a look at the dimensions and see if you think this could work for you.
Thanks for reaching out to us. 1-1/4" is unusually thick for a storm door. We unfortunately don't sell anything made to accommodate that size.
Not all hope is lost, though. You may be able to use one of our standard sets, like the 40-058 that Bob mentioned above, but it will take some minor alterations. Namely you will need to reuse the original screws (which will be longer than those that come with our set), or pick up new screws of the same size at a local hardware store. You will also need to reuse the spindle, which is presumable longer on yours.
That should be all you have to do; storm door handles are pretty simple in terms of function, so as long as they can mount to the door and as long as the interior and exterior handles are connected via spindle, it should be functional.