Replacing the loom

[armo]

Hi there just wondered if anyhow knew if trying to replace the loom is a easy task as when I got my bike who ever had it before had changed it to a single head light and cut alot of wires, and trying to track em back and extend is proving to be a pain,
And also was wondering if any1 knows where can get the leads that go on to the speedo for the lights as I don't seem to have any or be able to find any

Thanks