*SPOILERS*
I rather enjoyed the Children in Need 2005 special because it added a little more to when the Doctor regenerated and Rose having to deal with that. It was a nice little fan moment that didn’t fit into the Christmas Special that year, but does fit onto the 2nd series DVD. So when I heard there was going to be a Children in Need special for this year, I was interested but hadn’t bothered to do any research on it. As such, when I saw the episode, I squealed like a fanboy.
This mini-episode inserts itself between the 3rd and 4th series, specifically into the end of the 
final episode last series where Martha is leaving the TARDIS, but before the Titanic apparently crashes into it. Doctor-10 forgets to put up the TARDIS shields and as such, accidentally crashes into an earlier version of himself — Doctor 5 (ah, good old Peter Davison). Doctor 10 beams about seeing his earlier self and even has an explanation for not only why Doctor 5 looks older, grayer, has less hair, and is slightly bigger around the middle, but also why they have so few minutes together.
Doctor 5 is working to try to fix the mess, even remarking on the change of the console room. 
When Doctor 10 tries to explain who he is, Doctor 5 assumes he is some big fan, since the Doctor has done all these wonderful things and naturally would draw fans. The Cloister Bell brings Doctor 10 into action and he quickly manages to fix the mess. It is then that Doctor 5 realizes who he’s dealing with and how Doctor 10 had managed to avert catastrophe so quickly. I loved how Doctor 10 waxed on at how Doctor 5 was his favorite, because Peter Davison was always my favorite Doctor as well in addition to being the first Doctor I ever saw.
The episode managed to name-drop Nyssa and Tigan, and even had the two briefly gossip about
the Master. Apparently, it is a gay joke where Doctor 5 asks if the Master still has that daft beard but Doctor 10 mentions he has a wife. Apparently, “beard” is a gay slang for a homosexual who pretends to have a wife or girlfriend to disguise he’s gay. I didn’t know the Master was supposed to be gay, but apparently, many of our British cousins have believed this for ages and so there you go. I think these people are just desperate to have gay stuff forced on the rest of us, much like there was pressure to do so in the new Battlestar Galactica.
This mini-episode was pure fanservice with the return of Peter Davison’s Doctor. While the 
show’s executive producer has long voiced opposition to having a multi-Doctor episode, I guess that this was his way of tossing a bone to the fans since it is considered official canon to the Doctor Who story. The writer, Peter Moffat, again shows why he is a great Doctor Who writer with a good understanding of the past Doctor’s in addition to an understanding of the present Doctor, to say nothing of understanding what will get fans going.