You can apply at anytime you want, while you have valid leave to remain in the UK. Note however that an early extension may mean that you could short fall of the 5 year residency period required if you were to subsequently apply for ILR.shubhamsingal wrote:Would there be any issues with applying since expiry is 7 months away?
Do I need any extra documents to apply for this extension?
For documents required for an extension application, take a look through the Tier 1 (G) application guidance available on the UKBA website.