This tool looks like a bed or bearing scraper to me.  By this I mean for the hand scraping of a machine tool bed (lathe, Mill etc) made from cast iron.
The curve on it suggests that it may be also useable for scraping split plain bronze bearings, also for machine tools etc.    One scrapes off the high spots as evidenced by installing the shaft with engineers blue, clamping the bearing lightly, rotating and then removing.  This is repeated until the shaft turns freely, with the correct play.
It reminds me of when I was a poorly paid apprentice, back in the 60's, not very far from Sheffield.   I spent days at a time doing that.
I doubt you could use it on your Vanagon unless you've got some nasty rust spots!

cheers,  Steve Cotsford