Thank you guys for all your help and useful information, looks like I have to provide flatmate info (name, date of commencement and agent) – flatmate is due to leave back to China when their studies finish in Nov. so I will ride it out and provide if I get another. As for my parents and girlfriend, it looks like they do not have a right to demand that info – if I understand this correctly, they are not leasing and are just staying there intermittently.
The two people on the executive committee that do this on a regular basis are married retirees who seem to be obsessed with all sorts of issues surrounding the building (they place regular notices and come round to each unit asking about use of visitor parking ie are they in fact visitors etc, banning children from playing in the common area gardens (yes they put a notice up in the car park about that lol!!), and telling residents not to hang any laundry on any clothes line on or near their balconies). These things I just ignore seeing as they do not affect me but I was just annoyed that they come knocking on my door every so often demanding the information of my girlfriend and parents (why should I inform these two people about friends and guests I have over? seems to be a gross invasion of privacy, happy to provide info about who I lease to but no further).