Lateral from ER to IBD & US to UK

Hi all, 

I recently started my new role as an equity research analyst at a BB; however, I may have to move to UK due to family reasons. I am looking to move prob in 1 year. I have some questions abt the process:

Part 1: from US to UK

1.1. When should I start looking for a job? -- I feel like overseas recruiting may take several months, but how early I should get started? 

1.2. I have never lived in the UK before. Is there anything in particular (industry, work cultures, etc) I need to pay attention to? 

2.2. Should I contact headhunters in the UK? If so, when? How should I prepare? 

Part 2: from ER to IBD

2.1. I am looking to transfer to IBD or an investing role simply bc there are more openings. I recruited for both roles in college so I know what I will be doing. I am comfortable with fundamental technicals, but I don't have any deal experience. Is it viable to transfer from ER to IBD? How should I prepare for it? 

2.3. I also consider internal transfer but I have no idea how it works. There won't be many openings in ER so I am pretty sure I will target IBD as well. If there is anyone who's been through the process please feel free to drop any advice. 

My background: target school in the US, decent GPA, summered at the same firm and returned.