Joined: Nov 2006
Posts: 19,810
Likes: 597
From: NJ, NYC, LI
Bikes: 1940s Fothergill, 1959 Allegro Special, 1963? Claud Butler Olympic Sprint, Lambert 'Clubman', 1974 Fuji "the Ace", 1976 Holdsworth 650b conversion rando bike, 1983 Trek 720 tourer, 1984 Counterpoint Opus II, 1993 Basso Gap, 2010 Downtube 8h, and...
Hercules hubs appear on Ebay all the time. But note that the correct wheels on this bike are 32 spokes front, 40 rear. The rims should be Dunlop 26 x 1 3/8. I didn't bother to count the spokes in your photos, but I'm willing to bet your Shimano hub has 36 spokes so you will need to replace the whole rear wheel.
The correct wheel will turn up, in time; put out a search for it, but don't put whole lot of effort into finding it. That will only increase the price, if you know what I mean.
The correct chain guards appear on ebay as well.