Another option is to stop worrying about .45 Auto and shim the cylinder to go back to .455 Webley.
This works if you have, or can get .455 Webley ammo.
Around 20 years ago I spoke at some length with a fellow who was shimming the Webley cylinders. This is not a do it at home project, unless you are a gunsmith working from home.
If I remember right, he was using screws to attach the shim to the cylinder. One thing to consider is that not all the shaved Webleys were shaved the same amount. Some had more metal removed than others.
Shim thickness needs to be correct for the individual gun its going in. One size thickness will not fit all.
I have a 1917 Mk VI that has been "just barely" shaved. IT will still fire Hornady .455 Webley, but not 100% reliably. It does work 100% reliably with ACP brass and S&W half moon clips. It will not work with any full moon clip I have found. It will not work with .45 Auto Rim brass, there is enough clearance to let the cylinder close, but not enough to allow it to turn when loaded with .45AR cases.
Other guns I have seen had more metal removed and do work with AR brass or full moon clips.
There is something else you can try to make clipless ammo. take a .45 Colt or .45 Schofield and trim it to .455 length. The case body should fit, the rims will be a bit small in diameter, but are a bit thicker than .455 rims and this MIGHT work in a shaved webley, depending on the individual gun's tolerances. I say MIGHT, not "should" or "will" you'll have to test it in the gun you have in your hands to see if it work, or not.
I considered getting my gun shimmed and I considered using cut down Schofield brass but decided it wasn't worth it, I have enough clips that work and ACP brass in plenty.