for the record, the hack green bunker was constructed as part of the ROTOR project in the 1950's and modernised in the 80's to form an RGHQ centre (regional government accomodation).
(source: Hack green website)
either way, there are several levels full of equipment to explore both 'in period' and 'brought it' as part of the museum collection; so once you've been around the stalls a few times there's the rest of the day taken care of if you're concerned about it being worth while travelling any great distance.
