How much early we can submit a PBS dependant Application

[immi_enq]

HI ,

I have been granted ILR now. My wife's tier 1 general dependant visa is expiring on March 24 2013. I need to renew her visa before March 15 due to my travel plans. 28 days of expiry date would be FEb 25 2013 and I am bit worried If I will be able to secure an appoinment on between Feb 25 to March 8 leaving last five days for visa BRP card to arrive.

Is it fine to process the application in advance? If so, what should be the maximum relaxation we can ask border agency.

Any reference links from UKBA would be more helpful.

thanks and waiting for a response

[wpilr_nov12]

she can apply for extension any time before her current visas expires. Because visa extension does not have residency requirement as is for ilr

[immi_enq]

Thanks friend.