I would say, if at all possible, find someone who can repair and restore the original leather - it's amazing what the right person can achieve - I say right person, because it takes experience and the right materials to do it properly.
The main reason I say this is because you cant buy leather like the original any longer - Connolly no longer exists (in its original form) and they tanned and coloured the leather with a whole load of secret formulas (all, apparently, held in the head of a chap called Norman, who never wrote anything down - at least that's the story I heard). Also, the way Connolly tanned the leather changed over the years so a '74 Shadow has differently tanned Connolly leather to a 1990 Spirit.
Also, leather type aside, I've heard it is very difficult, ever for the best trimmer, to replicate the factory finish.
These people are ex-connolly, and worth speaking to, even if you are on the other side of the Atlantic. Very knowledgeable about restoring original leather:
www.leathercaredirect.com