OK, here's a slightly later Big Bob [1985ish, by the engine code]. As you can imply from monaro's post above, SupaSwift made mowers under both the SupaSwift and Vulcan brands, while they were owned by Vulcan, before the Allpower takeover.
This one has been in my family since new. It's quite original, with the exception of throttle control/cable, rear wheels, flywheel screen; and it's missing its muffler heatshield [that fell off and got run over one day].
The last pic is to highlight the feature that makes this one a second generation Big Bob. Note the gusset at the upper side of the handle bracket brace - this was an attempt to spread the stress, but wasn't all that successful. If you look closely, you can see a fracture on the near side!
The opposite side failed 10 or so years ago, and I repaired it by inserting an internal sleeve, and brazing it all up. This time, I don't have oxy welding available [bloody gas bottle rental charges], so the bracket will be replaced with one from a donor mower [see next post].
These mowers certainly haven't changed much over the years - the handle redesign and discharge chute is about it, apart from a variety of engine offerings.