In regards to Stonehaven, I have found that Mac Baren Old Dark Fired is the closest taste wise. ODF is not quite as sweet, but has more smokiness than Stonehaven, and I enjoy it very much.
Solani Silver Flake is not like Stonehaven other than it is a VA/Kentucky blend, but it is one hell of a good smoke.
I no longer smoke English blends so I cannot recommend annything similar to Penzance. Back when I was smoking Penzance on a regular basis, I never had to think of a substitute as it was always readily available. What I would do is start sampling all of the GL Pease English blends and see if there is something there you like. When I was smoking english blends, I found thaat no one did them better than Gl Pease or his line called Two Friends which is a collabotation with Craig Tarlar of C/D.
hiplainsdrifter, I find that Wessex Brown Flake and Brigham Klondike Gold to be fairly similar to JALF. I also enjoy Wessex Brigade Campaign Dark Flake even more than the JALF so grab some of that if you have not tried it. It is readily available at SP.