Mother Russia, the first of the new set of Companion Chronicles takes us to almost the same time as the first of the previous set - 1812 rather than 1814, Russia rather than London, and Dodo rather than Vicki as the companion accompanying Steven and the Doctor. Again, it is by Marc Platt, and again it is the best of the four. The comparison in my mind, however, is not with Frostfire but with Martin Day's novel Bunker Soldiers, which also features One, Steven and Dodo (though in Ukraine rather than Russia and a few centuries earlier) and indeed is also largely told from Steven's point of view in the first person. Mother Russia is certainly better. Partly it's that Platt has yet again gone for a fascinating plot of identity-switching complexity, partly also that Peter Purves is very good - he does a fantastic Hartnell, but also seems generally well engaged in the story.
I've seen some rave reviews of Helicon Prime out there; I'm afraid it didn't especially grab me, as I thought the plot was pretty unoriginal, but I felt that the planet of Helicon itself was well portrayed and that Frazer Hines made a decent effort at catching Troughton.
Old Soldiers was better than the other Third Doctor audios out there, but this isn't saying much unfortunately. The author can't spell the German name for the setting - it should be "Kriegskind" not "Kreigskind", and anyway neither makes much sense as a German name. I am going to add another note of pedantic snark and point out that neither part of Germany joined the United Nations until 1973, so German soldiers could hardly have been integrated into UNIT before then; yet we are told that the Brigadier has been working with his German colleagues for years, in a story set immediately after Doctor Who and the Silurians. Take that as my contribution to the UNIT Dating Controversy.
Havng said that, I think it is saved by the way in which Nicholas Courtney explores deeper levels of the Brigadier than we had seen before, and by the music which carries a great atmosphere of menace and doom. Courtney doesn't try too hard to 'do' the Pertwee voice, instead telling the story almost as if it were an official report, which works fine.
I had been looking forward to The Catalyst a lot, given my recently renewed enthusiasm for Leela. Well, it's a great story for Louise Jameson, who gets to play lots of different roles (she's pretty terrible at doing Tom Baker, but I don't mind) but I didn't like the plot; I generally hate the ones that depend on previously untold adventures, and here we have the Doctor and Leela visiting Lord Joshua Douglas, apparently a former companion of an earlier Doctor. And it never really became clear what was going on; horrible deaths happening all over the place but we never quite got to the bottom of exactly why.
So, try the first of these, and if you like it, experiment with the rest; good performances from the key actors, not so sure about the story in some cases.