It’s an okay start to the range but damn is the narration a little jarring knowing the rest aren’t like that

There's nothing wrong with Prisoners of the Lake; it's an enjoyable enough story on its own, but it's a very typical story of the Pertwee Era. Treloar does a relatively good job portraying Pertwee's Doctor; Katy Manning is also good here as Jo Grant, with her loyalty to the Doctor on full display and her bravery and competence. Mike Yates is present as well, and he's well-written and well-played.

A fun romp which fits really well into the Pertwee/UNIT era.  Tim Treloar is very convincing as the Third Doctor, although I do wish Katy Manning would understand that she sounds more convincingly young when she doesn't try so hard.  The set up - an alien stone spaceship at the bottom of the lake - is a good conceit but the script does end up just jumping back and forth between the ship and dry land for most of episodes 2-4 making it end up a bit repetitive.  It's a good guest cast though which holds the interest and, as someone who wasn't convinced the Third Doctor Adventures would necessarily be for him, as not being a huge fan of that TV era, I do now anticipate more from this series.