The Team TARDIS Diaries appears to have been an often delayed, short lived and now ended series of four books, only two of which were actually released.
It included these which were delayed for up to over a year or more and were eventually released :
#1 - Paper Moon by Louie Stowell - ISBN 9781405939539
https://www.amazon.com/Paper-Moon-Doctor-Who-Diaries/dp/1405939532

#2 - Ghost Town by Susie Day - ISBN 9781405939515
https://www.amazon.com/Ghost-Town-Doctor-Who-Diaries/dp/1405939516
The two upcoming books were :
#3 - Nimon of Athens - ISBN 9781405939553
https://www.bookdepository.com/Doctor-Who-Tardis-Team-Diaries-3-BBC/9781405939553
With this story no author was ever announced, however the title of this story that was to follow was revealed near the end of Ghost Town as pointed out in this online review on The Time Scales : https://thetimescales.com/Story/story.php?audioid=3710
#4 - Unknown - ISBN 9781405939584
https://www.bookdepository.com/Doctor-Who-Tardis-Team-Diaries-4-BBC/9781405939584
While this series was delayed multiple times it generally received quite favorable reviews. It is likely that the series was cancelled due to publication delays combined with the events of the TV series itself with the exit of Jodie Whittaker as the thirteenth Doctor as well as the cast of companions which were commonly known as 'The Fam" and featured quite prominently in these original two young audience friendly publications.
Kierra
Outpost Gallifrey News
London
It included these which were delayed for up to over a year or more and were eventually released :
#1 - Paper Moon by Louie Stowell - ISBN 9781405939539
https://www.amazon.com/Paper-Moon-Doctor-Who-Diaries/dp/1405939532

#2 - Ghost Town by Susie Day - ISBN 9781405939515
https://www.amazon.com/Ghost-Town-Doctor-Who-Diaries/dp/1405939516
The two upcoming books were :
#3 - Nimon of Athens - ISBN 9781405939553
https://www.bookdepository.com/Doctor-Who-Tardis-Team-Diaries-3-BBC/9781405939553
With this story no author was ever announced, however the title of this story that was to follow was revealed near the end of Ghost Town as pointed out in this online review on The Time Scales : https://thetimescales.com/Story/story.php?audioid=3710
#4 - Unknown - ISBN 9781405939584
https://www.bookdepository.com/Doctor-Who-Tardis-Team-Diaries-4-BBC/9781405939584
While this series was delayed multiple times it generally received quite favorable reviews. It is likely that the series was cancelled due to publication delays combined with the events of the TV series itself with the exit of Jodie Whittaker as the thirteenth Doctor as well as the cast of companions which were commonly known as 'The Fam" and featured quite prominently in these original two young audience friendly publications.
Kierra
Outpost Gallifrey News
London