Guys,
Firstly, Thanks a lot to all for helping me out with this. I would actually have gone ahead with half of the required documents had I not posted a query in this group.
Slight change of circumstances on my side. I have to fly back to India on an urgent basis (tomorrow night actually) so will be taking the documents along with me and my wife may not need to reschedule the appointment which is on this Thursday.
I went to my property agent to get a letter from them stating that my wife is allowed to stay with me.
However, they told me that it will take some time (a week or more) as they would need to contact their head office, landlord.. blah blah. Basically they don't want to do anything for which they are not paid. (I am highly frustrated with property agents in UK

)
So I don't think I'll get letter from the agents in time. (I am planning to go ahead with lease agreement alone. Does anyone suggest otherwise?)
Abhijack,
Regarding 15 months bank statements, I am including them to prove that I have been working in UK for more than a year and also that I am currently employed. (Not mandatory though)
Another doubt on this actually. For "Sponsor's proof of employment", wouldn't last 15 months salary slips, bank statements and P60 be sufficient? Or do we need to specifically get letter from employer? (I did not provide a letter from employer while filing for Tier 1 also and managed with sal slips and bank statement alone)
Reason why I ask this is because I work for an Indian software company and currently working in UK for them (Was on Work permit and converted to Tier 1). The letter from employer states terms of employment here and additionally terms of employment when I "return to India". Now actually I will not be returning to India since I have a Tier 1 , but due to the standard format of letter from employer, the "return to India" clause will be their in their letter.
This may cause confusion with the caseworker which I want to avoid.
I think pay slips also establish that I am employed in UK so Can I simply use the pay slips + bank statements + P60?
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