There are two options, an in-person event and a webinar:-
22 March at 12.30pm a webinar, book in via this link: HS2 and Align: North Portal and Chesham Road vent shaft engagement webinar – High Speed 2
23 March in person from 2.30pm to 7.30pm at Missenden Abbey, London Road, Gt Missenden, HP16 0BD: further details here: HS2 and Align: North Portal and Chesham Road vent shaft in-person engagement event – High Speed 2