I'm jinxed...
anyways, my contribution to the usual jigsaw puzzle of what actually happened
- I was on a southbound train from Leagrave to Blackfriars that was already running a little slow
- we terminated at St Pancras - driver was lovely and very apologetic, he was basically only told a minute before he would be terminating and heading back North. It took several minutes to empty the train, for driver to walk up trains/check doors, for platform staff to work out what on earth was happening, for someone to remember to tell passengers to scurry from one platform to another, and then to finally dispatch the train.
http://www.realtimetrains.co.uk/train/G71589/2014/12/08
(Instead of bothering to attempt to go via the circle line given the trek through St P etc. I decided to sit and wait/watch

)
- the next couple of southbound trains were late/cancelled, so the next service to depart the southbound platform that was actually going south was then headed for Sutton (and I got on). it left 8 minutes late
- but...then (and this was the daft bit...instead of having used the waiting around while the u-turn train didn't run through the core for bi-di), this first south train was then held outside farringdon for 15 minutes while 3 trains went around the failed train (they passed us in tunnels). We were then on our way again.
http://www.realtimetrains.co.uk/train/G71830/2014/12/08
- when we went through City Thameslink, it didn't look like a standard failure. The train extended beyond the platforms towards blackfriars by a number of carriages (so ???either failed going into City, or failed when trying to go back the way it came, or a train shunting it failed to move it - I wasn't counting properly..but it seemed quite long given the stock)
Delay repay claim 32 minutes
Sorry for the long post, but hopefully fills in some of the gaps and around bi-di was used in practice.
[samuelmorris - bus 214 or 205?]