The third volume of the annotated Yale edition of the original Life of Johnson manuscript has recently been published and is now available worldwide. The long awaited volume has been edited by Prof. Thomas F. Bonnell who is also already working on the fourth and final volume in that particular sub-series of the Yale research editions.
As stated by the publishers, the Yale Life of Johnson Manuscript volumes offer "a genetic transcription, forming an edition designed to make this complex document accessible for the first time. Supplemented by textual and explanatory notes, the transcription enables readers to trace changes Boswell made in the process of composition and printing, restores lost and deleted material, and corrects a range of previously undetected errors and misreadings."
The volume is available from Amazon UK (also best option for EU citizens) and Amazon USA.