When thinking about where you want to stay perhaps you should consider the following points:
Do you want to live close to your work place?
Can you afford to stay close to your work place?
If it is no to the above
How long can / do you want to spend getting to work, that will give you an idea of what radius, areas or specific areas you might want to avoid.
Have a look at the transport links to your workplace.
Find out how much it will cost to travel to work using those links.
What type of life style do you want for your family, is it to be mainly British based or Indian based. There are not many areas that are well mixed so you might as well choose to be either one or the other.
Do you have children? If so you will not readily get a one bed roomed place unless the child is under two. If you have more than one child the only landlords that would let a one bed roomed place to you are the very people you want to stay away from.
The further out of Central London you go the cheaper in general the rental market BUT be aware the rental market is booming at the moment and the prices are going up not down despite the housing market price collapse.
To find out about crime in an area use the internet to get an idea when you are looking at places. See link:
http://www.upmystreet.com