From IB to Growth Equity / VC (Europe) - How?

How can one make the jump from IB to Growth Equity / VC coming from IB/M&A? 

• Is it all a matter of headhunting?
• Which are the top firms in London/Europe?
• When would someone aim to make the move? After 1/2 years in the sell-side? 
• How can one maximise exit opportunities? 

Do you have any tips? 
Thanks!