Colin Rosenstiel wrote:

Must have changed since I last used Marylebone then.

That's quite possible, actually. The new gates went in when the barrier line
was renewed last year, just before the new platforms 5 and 6 were opened.
Prior to that, with a bike you had to use the "big" vehicle access gates at
the side of the barrier line, nearest platforms 1 and 2.

Platform 4 has now been shortened, ending just outside the main trainshed,
and the old trackbed infilled and paved over (making the bufferstop line of
platforms 4, 5 and 6 parallel) with access to these platforms via the very
wide walkway that has been created from platform 3 to the wall that used to
be at the back of the platform 4 road; the bicycle racks have also been
relocated to that area. A new barrier line has been installed behind the
ticket office, with a wide gate, primarily to give access to platforms 3-6
(although they can be used and the wide gate *needs* to be used for access
to other platforms as well). The original barrier line in front of platforms
1-3 has been renewed, with a second wide gate (normally for exit from all
platforms), and a mixture of entry and exit gates.