There are offenses but I don't think that speeding is a bicycle offence:

In this forum, link below:

http://www.bikeradar.com/forums/viewtopic.php?t=12545036&start

lawyers state that because bicycles are not classified as motor vehicles, *speeding* is not a bicycle offence:

The Road traffic regulation act 1984:

http://www.statutelaw.gov.uk/content.aspx?activeTextDocId=2223862

does refer to "motor vehicles" :

Part VI
Speed Limits
81.
General speed limit for restricted roads.— (1) It shall not be lawful for a person to drive a motor vehicle on a restricted road at a speed
exceeding 30 miles per hour.

Speed limits on roads other than restricted roads.—
[ F332(1) An order made under this subsection as respects any road may prohibit—
(a)
the driving of motor vehicles on that road at a speed exceeding that specified in the order,
(b)
the driving of motor vehicles on that road at a speed exceeding that specified in the order during periods specified in the order, or
(c)
the driving of motor vehicles on that road at a speed exceeding the speed for the time being indicated by traffic signs in accordance with the order.