Hi All
I'm also from the Tube Forum, I'm known as Iain over there (Tangy there's also a new full network time of 18:49 something earlier on in the thread).
The current record is 16:29:13 set about 18 months ago by Andi James and Steve Wilson. It's generally considered (I've had nine goes) to be tough to beat. As already mentioned the record has been made harder to try because of changes to the Kensington Olympia services, although there are still services every day, so if you plan your route correctly you can synchronise with these.
Geoff of the website already mentioned and former record holder has created an App called StationMaster which is probably the best one out there for door positions, which makes sure you're bang opposite connecting passageways on interchanges. It's worth looking at them still beforehand so you know how to run and aren't left frantically looking at signs trying to find the line you need.
There's lots of other tips, but people may well be wary of giving away too much information. Here's a couple though - have a look at physical station location so you know which ones you can run between (use an A-Z). You're also allowed to use scheduled public transport - so buses and trains for instance but not taxis. Most routes will make use of both these tips.
Come over to the tube forum though, I think every question you've had has been answered over there plenty of times; there's also lots of other insight plus various events organised with teams racing around the tube.
