Putting the rants to one side for a moment, it appears to me that the accident rate on country roads is a largely the (unintended) result of policy regarding how speed limits are set and their enforcement.
Prior to the "speed kills" mantra becoming the be all and end all of road safety in the UK, speed limits were exactly that: the fastest speed that it was deemed could be used safely on a particular road. Drivers were required to develop skills and judgement and determine a safe speed at which to travel within that limit, according to conditions. An unexpectedly low limit on a road that appeared not to warrant it would be an important clue to an experienced driver that there was some sort of hazard that wasn't immediately recognisable, and would be the cue to slow down and exercise extra caution. Since the focus on speed limits and speed enforcement, things have changed. Limits have been set on a lowest common denominator basis, with a plethora of reduced limits around junctions and other hazards, and drivers are now told that as long as they're driving at or below the posted limit then they'll be safe. No longer can an experienced driver use the presence of a reduced limit for which there appears to be no obvious reason as an important cue to modify their speed and use extra care. And instead of using judgement and skill to set an appropriate speed at which to travel, the dumbed down driver just rolls along at whatever speed the limit signs say, abdicating responsibility for that decision to the authority who set the speed limit. Now put those same drivers in a rural road setting, with its variety of hazards, and they lack the competence to decide whether 60mph is either safe or appropriate with potentially awful consequences.
The second issue is the principle of displacement. The facts are that driving quickly is fun, that the most appropriate places to drive quickly are divided highways with graded junctions (i.e. motorways and high-spec dual carriageways), and open A-roads with good visibility. But those are exactly the places where exceeding the speed limit, even by a relatively small margin, will result in a fine and points on the licence. So, the only place left on the public roads to drive quickly - and safely, if the appropriate skills have been developed - with low risk of sanction for a minor limit infraction are those where it is arguably the least safe to do so: rural roads. Now our dumbed down driver, frustrated at the endless miles of inappropriately slow 40mph andn 50mph limits that infest some of our better roads, swaps to driving on country roads with their 60mph (national) limit and tries to drive at that speed regardless of whether its appropriate or safe to do so.
This is a problem that has been caused by policy elsewhere. The introduction of new DfT "Guidance" regarding the setting of limits on rural roads will not solve the problem, because the problem hasn't been correctly analysed and the "solution" is inappropriate. What it will do is allow the uninformed amateurs in local councils to deploy yet more irrelevant limits which make it even harder for drivers to judge which ones really are there for a sound reason.