I'm pretty sure I just copied the "8 stage demo" from the magazine. I admit I never played all 8 levels, just WHD'd it enough to work and released. It is probably 7 and a typo in the magazine or something. No idea sorry.
Also the WHDLoad patch works fine on my WinUAE here so not sure what your problem could be. Hopefully not a pirated WHDLoad key!
Update: I got the 8 level information from the disk label on the front cover of Amiga Power issue 41