lateralling Internationally < 1 year into the job

Monkeys, 

Coming here for help as this forum has provided great wisdom in the past. 

For background, I am currently classified as a first year analyst in the M&A team at an American BB in one of their overseas offices. I have been on the desk now for 9 months now and my bank requires 12 months of service before even having a discussion about moving. Even then, they recommend moving as an Associate after a long process. In my mind, the best case scenario looks to be moving after 2-2.5 years into the job and approaching an A2A promotion, when I want to realistically move as an analyst.   

I am hoping to move to London or New York ASAP and due to my firms policy, am considering trying to lateral to another bank. In a worst case scenario I would want to hit the desk in June next year. Given there is three months gardening leave, I realistically need to start looking at applying soon. 

With that in mind, here are some questions / feedback I would love to get from the forum: 

• Obviously it isn't a great look leaving a job less than a year in, but would it be seen as "more acceptable" given it is an international move?
• If the answer to the above is no, when would be an acceptable time to begin applying to other jobs? January - March? 
• Does anyone have any advice about lateralling internationally? Visa issues won't be a concern. 
• How would you approach the conversation with my manager and HR? 
• Is there anything I could say internally which may make them more inclined to facilitate a move sooner? 

Any other thoughts / wisdom would be really appreciated. 

Thanks.