Please – otherwise I fear I could be here a while…

Straightened wire coathanger as a guide with the cable duct taped to the end.

use a straightened out wire clothes hanger, works a treat.

I always found it easy to start the cable install by doing the swingarm first so that you have the rest of the cable free to twist & turn
insert it from the seat tube end & then keep tuning it – like a crank handle – until it either fouls itself or you can see it enough to fish it out

probably not much use this time but next time….

pull old outer off leaving inner in place.

cut nipple end off old inner.

slide new outer over old inner top down.

pull out old inner and replace with new one.

ta daa!

What they said about coat hangers, or any bit of wire that holds its shape.
Also a tip, whenever you remove a cable or hose from an Orange swingarm, attach the guide wire before you pull said cable/hose out of the swingarm so its already in place as a guide for when you are ready to reinstall it.

Thanks all – yes unfortunately I bought it frame only with the existing cables removed

colourful language and a large field.

I did this on Saturday with my new frame in about 5 mins.
Pushed cable outer through from backend of swingarm and with a torch I could see it just below the exit at the front of the swingarm. Made a hook out of the wire that comes with Shimano brakes to secure the bolts with. Pulled outer back a little, dropped in hook, pushed back outer and then lifted up with hook and then managed to pull it out. Put the plastic grommet thingy over the outer, slid it down and pressed this back in place.