The Stageplays adaptations was certainly a novel idea for Big Finish to give some new life to Doctor Who productions that later generations would not be able to see live. But there is a very good reason why there's only been three of them (admittedly out of six total plays). The first of these being The Ultimate Adventure, adapted from the same play from 1989 which starred Colin Baker, Jon Pertwee and even David Banks playing his own version of the Doctor. This adaptation uses the Colin Baker version as he and his companion Jason (short for a name I'm not even gonna try and spell out) get caught up in an "ultimate adventure" if you will involving Daleks, Cybermen, mercenaries, Margaret Thatcher (???) and a new companion called Crystal.
I'm sure the actual play was a lot of fun for fans who got to see it live but it really doesn't translate to audio. We get music numbers that go on for way too long, usually when Big Finish do songs they either keep them short and sweet or make it clear what's going on during the songs, these on the other hand is just listening to the actors singing into a microphone for three minutes, when the play version I'm sure would've added a lot more visuals to it, such as the romance song being on a planet with low gravity probably featuring the two singers elevated off the ground.
The biggest issue with this story is the fact that it's too simplistic, the characters are very one dimensional, the dangers we get are too frequent and get sorted too quickly so you never feel like there's any tension. Being a stageplay isn't even a valid excuse as it's roughly the same lenght as your average Classic Who story and they seem to manage fine with characters with more depth and situations that require more effort put into them. We also get a ludicrous ammount of lines describing what in-universe are right in front of the characters eyes and even worse, describing things that we the listeners can clearly tell is happening, such as the TARDIS being "destroyed". Writer, Terence Dicks, originally wanted to write a novelisation for this play but Target Books refused to publish and frankly I don't blame them, The Ultimate Adventure is mostly just a cliffnotes summary of what a Doctor Who story is like which I'm sure was fun for the audience who got to see it live but for listeners is just completely lacking in substance.