@GrandmasCat
Is that a new rule at all? It was always specified that you need to leave enough space when overtaking bikes and horses as if you were overtaking a car. That is approximately 2 meters and that rules has been there at least for 20 years!
You’re right, it’s always been in the rules of the roads to leave appropriate space, and also with the other ‘new’ rule, it’s always been against the rules to run over pedestrians crossing
The new rules give guidance on how much space to give.
Leaving 2 metres space when overtaking is advising people to actually overtake by moving over to the other lane. If you can’t go out across the other lane to overtake then there isn’t the space to overtake
For narrow country lanes quoted by the OP, if there isn’t the space of another lane then oncoming vehicles are more of a problem, the OP needs to slow down and pass other road users at the passing points.
A friend of mine once encountered a tractor towing a long trailer on a narrow country lane whilst she was driving a horse lorry.
Neither could pass, the nearest overtaking point was behind the tractor but his combined tractor and trailer were unsuitable to reverse along a country lane, her lorry was too big for her to see to reverse and avoid being hit by anyone coming up behind
The tractor driver got out, directed her to reverse, got back in his tractor and drove to catch up, got out and directed her ….. etc
It took time, but common sense resolved the problem of long vehicles meeting on a narrow lane