Complex sentence: This takes on a greater significance as it is only the high point of the Coniston Fells by a small margin, The Old Man of Coniston being within a few feet of parity.
Split into simpler sentences: This takes on a greater significance since if it is the high point of the Coniston Fells, it is only so by a small margin. Its near neighbour, The Old Man of Coniston is within a few feet of parity.