That particular cage was made for large parrots. I can tell you by personal experience, that I had budgies (standard not English) be able to get their entire body through a 1” bar spacing, and get in and out of my parrot’s cage with surprising ease. (A long time ago, and budgies were put in another room), but mentioning it because they will try
to get through at some point. An English might be able to get tragically stuck in 3/4”.
If you’d like a very large cage for budgies, I would look instead at indoor aviary cages. Ones made for small birds. No more than 1/2” bar spacing.