Return of documents by post?

[Chikky]

Hi

my mother is applying for UK family visitor visa on 10th April 2015 from Mumbai and then she is traveling outside Mumbai down to south for a wedding.

What is the process to get back the passport and the original documents? I had couple of questions:

1. Do they return the passport and the original documents by post? or do we need to physically go and collect it from the visa center?
2. If they return by post , then can they return by post to a address in South instead of Mumbai so that my mom can collect the documents.
3. If they only send by post to Mumbai address is it ok to ask them to deliver it to another address in mumbai where someone can receive the documents on her behalf?

how long does it take for the visa?

Thanks