Malcolm, I assume you have tried the QB 4.5 code in QB64 and it doesn't work?
Is vDosPlus one of those DOS apps like DOSBOX that lets you run DOS apps on a new computer?
GTC, I don't know how practical it would be for you, but you might want to look at this option?
Again, I hope I'm not speaking out of turn.
I'm reasonably prominent in WordPerfect for DOS circles, and in that world, many people have moved over to running WordPerfect under vDOS, a business-friendly variant of DOSBOX that aims to do more than just gaming. So it prints, etc etc, unlike DOSBOX.
Its weakness is that it doesn't handle DOS programs that rely on certain interrupt codes. QB45 uses these codes. VDosPlus is a fork of vDOS that does handle these interrupt codes, and so I use it as the nearest thing I can find to DOS, in 64-bit machines. (Although, in point of fact, a lot of my day-to-day work is still done on a 32-bit machine.)
I have a bunch of QB45 programs that are important to my work. (I'm mid-60s, but not retired.) Being somewhat paranoid about what Microsoft might do next, I tend to keep my options open. I run Ubuntu Linux as well (which is superb), and as a matter of policy keep these QB45 programs going on both QB64 and QB45-under-vDosPlus.
I have long since stopped keeping them going under Liberty Basic, which is what I was doing prior to QB64.
I'm not an especially active coder, but I add to these programs at the rate of one or two a year, as the need arises. Some of them go back to Commodore PET days.
So there's a long answer to your question, but hopefully you can see where I'm coming from.
Malcolm