AFAIK, to get into the statistics of the type you describe, it has to be the subject of an accident report. A lot of this is geared up to the duty of the driver of a motor vehicle to report an accident to the police. That talks about injury to any person, other than the driver of the vehicle, or to any animal, or damage to property. Rightly or wrongly, fall off your bike without the contribution of a motor vehicle and I don't think it's going to go in an accident book. Remember, the police are looking for evidence for a prosecution, anything of value to a civil claim is a by-product of that. Sometime when it's rainy, I'll see if I can find something in writing, but this is one of those things I think I just know.
Meanwhile, back on the civil law, as opposed to police procedures, the duty to maintain a highway is in relatively modern legislation, and it's in the Highways Act 1980.
Highways Act 1980
41.
Duty to maintain highways maintainable at public expense.— (1) The authority who are for the time being the highway authority for a highway maintainable at the public expense are under a duty, subject to subsections (2) and (4) below, to maintain the highway.
(The exceptions are all administrative and nothing to do with this IMO.)
The usual negligence actions against the authorities are because of alleged unrepaired defects, irregular footways being said to be the happy hunting ground of slippers and trippers. Here's the highway authority's
special defence to a civil action for negligence which is in section 58 of the same act:
Special defence in action against a highway authority for damages for non-repair of highway.—
(1) In an action against a highway authority in respect of damage resulting from their failure to maintain a highway maintainable at the public expense it is a defence (without prejudice to any other defence or the application of the law relating to contributory negligence) to prove that the authority had taken such care as in all the circumstances was reasonably required to secure that the part of the highway to which the action relates was not dangerous for traffic.
(2) For the purposes of a defence under subsection (1) above, the court shall in particular have regard to the following matters:—
(a)
the character of the highway, and the traffic which was reasonably to be expected to use it;
(b)
the standard of maintenance appropriate for a highway of that character and used by such traffic;
(c)
the state of repair in which a reasonable person would have expected to find the highway;
(d)
whether the highway authority knew, or could reasonably have been expected to know, that the condition of the part of the highway to which the action relates was likely to cause danger to users of the highway;
(e)
where the highway authority could not reasonably have been expected to repair that part of the highway before the cause of action arose, what warning notices of its condition had been displayed;
but for the purposes of such a defence it is not relevant to prove that the highway authority had arranged for a competent person to carry out or supervise the maintenance of the part of the highway to which the action relates unless it is also proved that the authority had given him proper instructions with regard to the maintenance of the highway and that he had carried out the instructions.
I think I'd struggle to find anything in there which said that the duty imposed on the authority by section 41 to maintain the highway was removed in this case by anything there. The standard of reasonableness tends to be set by expert evidence from 'independent' highwaymen on the basis of mutual solidarity, but I don't think anybody could keep a straight face and argue, for example, that under (a) a cyclist could not reasonably be expected to use a cycle track, and in particular the officially signed access point.
Anyway, I'm no lawyer and you don't keep a dog and bark yourself.