when is the earliest i can apply for TRV ?

[lenk_helen]

Please advise when is the earliest I can apply for TRV for my child (non PR holder) in London. My husband and I are PR holders (daughter applied, had immigration visa, but never landed) and in this forum we were advised to apply for TRV for her first, before considering other options.

If the proposed trip is in June- July 2012 can I apply this year ? or if next year when is the earliest so we have time to explore other options should the visa be declined (we must go back to Canada in early September 2012, not to loose our PR)

Thank you !