1. your old loom =
1.red = permenant live
2.brown = earth
3.blue/white = illumination
4.brown/red =ignition live
5.yellow/white = elecrtic ariel
These designations i am quite sure of as they have come out of a bently manual.
Warning the following is only based on assumption and we all know what assumption is the mother of all...........
your new loom =
10.red = ignition live
11.black = earth
12.blue = illumination
13.yellow = permenant live
These are only assumptions but if you post a piccie of the wiring diagram we can tell you for certain?

try connecting them in this format:
old loom? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?? ? ? ? ? ?new loom
1.red = permenant live.........................13.yellow = permenant live?
2.brown = earth..................................11.black = earth
3.blue/white = illumination....................12.blue = illumination
4.brown/red =ignition live.....................10.red = ignition live
5.yellow/white = elecrtic ariel................ not used