????
Adrian, unless the pictures you posted have turned upside down or something crossing the equator, that looks like a pretty standard inclination of the bed. I wouldn't take too much notice of the blade, it's so worn I would not know which way to put it, but a new blade with a standard sharpening bevel should sit in it like a normal cutting blade, methinks. You have the option of flipping the blade in just about any single-iron plane to get a scraper of sorts.
As to the purpose of your plane, I have no idea other than it looks like it's intended to plane rebates in situations where a bit of stand-off from whatever is above the shoulder being planed to is desirable. Someone posted
a similar plane on the Ubeaut forum last year, which provoked a good discussion, but no clear conclusions.
My first thought was something a coachmaker or patternmaker might use, but one of the respondents to the discussion is a retired patternmaker with wide experience & it was not familiar to him. I'd make a small wager it's a coachmaker's weapon - they had all sorts of rebate planes to handle all sorts of complex rebates, and the fact that planes like yours came in both straight & curved-sole versions reinforces that notion. I guess the trade has never become totally extinct, but there would be so few practioners left that it's unlikely one reads posts like this & will give us an opinion from a position of firm knowledge, but maybe one of our old-tool-savvy members will come up with a good answer for you...
Cheers,
Ian