Big Finish: Doctor Who The Gray Man of the Mountain

Listening to The Gray Man of the Mountain, story is pretty solid. But when I saw Jon Culshaw as the Brigadier I was very reluctant about this. Yes I am kinda familiar with his work but mostly as Tom Baker and Jon Pertwee Doctor's.
So happy that my concerns were not needed. Culshaw brought the Brigadier to life. He just didn't have the voice down but those little nuances that Nicholas Courtney had. I can't really think of many but one, for me, is that the Brigadier would pause in mid sentence before asking the Doctor a question, as you can "hear" him think of the best way to ask his question to a non-military personal.
So to make this a discussion have anyone else been surprised by a voice actor? Doesn't have to be in Big Finish it could be BBC or other audio books. I am curious to see "new" stuff for me to look into. Thank you in advance.

Jon Culshaw has done the past two 3rd Doctor boxsets as The Brig and I've been comfortable with it. Overall the 3rd Doctor sets with Tim Treloar have been good and I'm getting used to his 3rd Doc. Their "Liz" (actually it was Caroline John's daughter) has a completely different pitch, but did manage the mannerisms well enough that I was able to recognize her as playing her mother. Not quite like Mr. Culshaw where I forget he isn't Nick Courtney sometimes, but still a good recast.

I'm hoping the Sadie Miller "Sarah Jane" adventures with Tom Baker turn out at least as good as Liz did.

Oh, and the BF Ben Jackson by way of Elliot Chapman was excellent. It permitted a whole load of 2nd Doctor adventures with Ben and Polly and even gave Ben the spotlight once or twice. With so little of Season 4 remaining it was nice to get more of that TARDIS team.