Barge board repair

Hi guys , First time poster long time reader .( great site ) .I have been renovating my cal bungalow (1924) for a the past year . Re plastering the old crumbling lath walls ,polishing boards ,re- carpeting , and re cladding weather boards and i have sourced a heap of info from you guys ,Thanks.
My next job is to get the old terracotta roof replaced $$$$$ ouch. First i need to replace some rotten barge board ends and scotia that the mortar is bedded onto . ( similar to thread previously posted ) . Would you guys replace the entire barge or just the rotten ends which appear to be rotten 1 to 2 metres up from the ends . Barge is approx 6 metres long on each pitch.Keep in mind that as a chippy i make a great sparky .:2tsup:

Cheers
Chris

Sure you can join with a miter but it will always be visible. For the extra cost of a full length you can use treated timber which is rot protected.