Tfl website tells me there is some.

Anyone know where, and if it's busy enough that my bike would be one of
many left there overnight - or if it would be the only one?

Bike looks my best (quickest) option for getting there at 0400.

Thanks

Colin McKenzie

--
No-one has ever proved that cycle helmets make cycling any safer at the
population level, and anyway cycling is about as safe per mile as walking.
Make an informed choice - visit www.cyclehelmets.org.