sorry i forgot to say
so...
to the forum
as far as i am aware the k2 is and easy fit, as mentioned before there was a batch which needed some tweeking as they didnt sit right, but is sorted now i believe. k2 is best if you dont want to upset the neighbours.
i went for the k1 as its a good price and my neighbours really wont care, in fact, one of them will be fitting it for me