I may just possibly have mentioned that before considering adding more locks to the normal pair of locks that a front door would have (latch and deadlock) a London bar should be next. It’s called a London bar when it has a hoop to go over the keep of a rim latch (a “Yale”).
When correctly sized (no gap between the bar’s hoop and the latch keep), and when set slightly back, the London bar doesn’t impede the latch bolt slipping over the edge of the keep (the ‘strike’), i.e. allowing the latch to latch.
Some latch locks (Union do a common one for example) are mortice rather than rim: they go in the door rather than on the door. In which case, you would use a Birmingham bar – one that doesn’t have the hoop.
However, especially with a thick door, no matter how far back you set the Birmgham bar, the latch bolt is going to hit it first. That may be OK when new. The powder coat will probably be smooth enough. But even a good bar’s powder coat will wear off, leaving the latch bolt striking the bare metal of the bar. You may get away with it; but you may not. You may find that no matter how you slam the door, the latch bolt simply hits and bounces off rather than slipping over and into the keep. The only way to get the door to shut is to use your latch key; which isn’t the point of a latch at all.
You may find yourself having to file a bevel on the edge of the bar where the bolt is striking it. This is often worse on the cheap London bars that have an “H” profile.