Hello,
I looked more closely at the profile. The side in my pic is almost a wedge, and the 'hollow' side looks like it's quarter-hollow.
I put 2 layers of tape on the spine and started honing again on the 400. Got a fairly decent edge on it after about 20 mins, but I have shaved a lot of metal away! It's my first go at actually restoring an old blade, so I didn't expect it to go well! I'm determined to put a shaving edge on it and shave with it, even if I scratch the face up in the process. I never meant to sell it on, it may even turn into a decent razor to shave with, just not to look at!
I have my own hollow-ground razor which I have maintained for a year, so honing is not an issue. This blade looks like it was just badly made, or for some reason the makers only hollowed out one side.
I have 4 more old razors to practise on for now, so I'm hoping the next will be a bit more successful.
Lots of good advice in here, which is one of the reasons I thought I'd give it a go.
Cheers,
Mark