Hi, I know this is a late response to your post, but I just found the site.
I just sent in my form for the NIM and I will be living in London (without working) as of June 27th.
I agree with you about the lengthy process! I contacted 4 agencies and they all stated the same thing - 4-6 months is the soonest.
If you are still around, and any other nurses out there, please post!