I travel around 8.15pm and either get the 08.17 Overground to Canada Water in which case I never get a seat. However you are able to stand further down the carriage which is much more pleasant compared to standing in the crowded end by the doors (I feel especially sorry for the people getting on at Brockley as it's packed by then!).

The change at Jubliee is not that bad, it's just that as people get off the Overground a bottle neck is created as there is only one escalator. However at the worst, it's only a couple of minutes you have to wait and in most change-overs the time distance would be greater as you'd been walking through tunnels to a totally different line i.e. at Waterloo changing from the Jubliee to the Bakerloo.

Re the train: when you know where the carriage doors are, I generally do get a seat on the 8.12 or 8.21 train to London Bridge although certainly not all the time. In the evenings, I always get a seat on the train but that's because I'm early to arrive for it.

I have lived in north and south west London and the journey on the Northern line was a nightmare. It's much better being over ground compared to a dark dirty tunnel!

What I will say is that if you live at Honor Oak you will NEVER get a seat in rush hour whether you're on the train or the Overground.

Good luck with your move. SE23 is a great place to live and it's a very exciting time for the area so if you to decide to move east, I don't think you'll regret it!