I'm going back perhaps as much as 15 years, and only have vague memory of the procedures, but Tony sounds as though he may have a b
d boot sector or two. When hard disks were over a thousand quid for a 330
Mb. I would get up to all sorts of tricks to help people who I might woo away from their existing dealer.
The latest drives just may not be applicable, I just don't know, but here's what I would do up to about 1999. Oh, BTW, I don't have any software now that would do the job. What's needed is the soft for that disk, that will do a low-level format. Are such programs available? But if not......
When I was certain that the existing low-level format was finished, I would re-format it with a simple utility that would give a linear format. That is to say that all the cylinders had the same number of sectors. Okay, that reduced the capacity and indeed the speed, but surprisingly a user couldn't really notice the difference.
Then getting it going was a matter of F-disk and ordinary formatting. Now, here's a thing. I could cheat by putting a DOS 6.22 operating system on, hanging in a 1.44 flop if needed. Then pushing it up to whatever windows was current. I did this for years, right through to 98SE if I'm not mistaken.