After some thought, I have tweaked the numbers required to earn Time Lord and Castellan trust levels.
You can read all the in-depth numbers here (and this explains what trust levels do) but basically:
Time Lord is now a little more difficult to earn. You must give and receive 10 likes before being promoted. This prevents lurkers who only randomly post a few messages from gaining access to the Members-only area.
Castellan is a bit easier to earn. You now do not need to read as large a percentage of new posts over the course of 100 days to become/remain a Castellan (reduced this by half).
This is because we have a LOT of topics (for example the daily Whodles) and a LOT of posts (for example random musings in “Free for all chat”) and it should not be necessary to read all that, you should be able to become a Castellan even if you only focus on things like the clubs and chatting about latest releases.
To counteract this slightly, you need to give and receive far more likes - a Castellan has to give 200 likes and receive 200 likes, every 100 days, to remain. Spread the love! 
Looking forward to welcoming a few more people into the Castellan club soon!