HS2 Ltd had recently published a document, a new corporate report titled 'Corporate Plan 2020-2023 Building Britain's future. I think it was posted by me or somebody else in this group (In any case, I place the link as a comment).

This link summarizes the timeline of the tunnel construction activity in London using that documents.

https://www.ianvisits.co.uk/blog/2020/09/02/hs2-outlines-timeline-for-london-construction-works/