hey lofty i have just had new new lines professionally fixed and while i was helping i noticed how they put a new sleeved loop on
first you will probably have to cut the lines to the are all the same length and then put a new sleeves (white line through the colored line) on all the lines and then loop them round on themselves and sew the loop together.. hope that makes sense.
kind of like this but sewn at the end instead of tying knots.. hope this helps