I went through the menepause about 10 years ago now I occaisionaly get some spotting of blood - it is never very much and is not enough to warrant sanitary protection - it is just a few spots and then it's gone but I do sometimes get a light brown discharge
At my last scan the nurse said my vaginal walls were bleeding slightly due to hormone imbalance - could this be related and if it is why is there just so little bleeding?

Yes this is correct. The brown discharge is actually old or dried blood. Your body is still changing and this is quite normal.