Very, Very Westcoast Terry.
I'm very much looking forward to the fact he has 2 new albums due next year and features on Rage Of Angels!
He released 2 solo albums, and an album in 1989 as Distance (with the guys from Power Station I think... minus Robert Palmer).
He has also released a live album from his time with Bad Company as "Robert Hart's Bad Company Live At Hampton Beach" (although it was actually Bad Company, not Robert Hart's Bad Company playing on the album, recorded around 1995, with Robert, Mick Ralphs, Dave Colwell, Rick Wills & Simon Kirke.
He released 2 singles, "We're Not Coming Home Empty Handed" (a football themed song) and "We Will Remember Them" (a brilliant charity single for the Troops! Prefer his version to the all-star version that was released by Paul Carrack, Paul Rodgers, Mica Paris, Haley Westenra, and Michael Bolton...)
The band with Rick Wills and Kenney Jones was The Jones Gang. Was a very good album, but we won't ever see a follow-up I believe, as Kenney and Robert have fallen out (or so I was told...). Danny Bowes was the last person fronting the band for their live charity performances.
Robert has also fronted Company Of Snakes (replaced by Gary John Barden of MSG, and then Steffen Berggren of Snakes In Paradise), Apart From Rod (Rod Stewart's former guitarists, Jim Cregan, Robin Le Mesurier and Gary Grainger, playing the classic rock material of Rod with Robert on vocals. He was replaced in this band by Ben Mills, a very Rod-esque singer from the 2006 UK version of X Factor) and most recently he is fronting Manfred Mann's Earth Band.
There ya have it! If you can get his 2 solo albums (Cries & Whispers and Robert Hart) and the We Will Remember Them single as well as Jones Gang, you have a good round up of his work. His first album with Bad Company from 1995, "Company Of Strangers" is also very good, and took Bad Co back in a more bluesy-melodic rock vibe after their out and out American AOR sound with Brian Howe up front.
Hope this helps!
Niv