Thank you gentlemen.
The answer seems to be 'brake by wire but mechanical backup, with the paking brake mechanical'. The bit about the parking brake being purely mechanical did sound a bit odd at first but thinking about it it does have to work when the aircraft is powered down so perfectly logical (also reminds me of the comment on the David Gunson tape of 'you, as co-pilot, should make sure the handbrake is off. Otherwise when landing we will get a smell of burning rubber followed immediately by 18 loud bangs').
As to the 'fly with total loss of electrical power' comment I would have thought that on a large aircraft (and I am speaking from a possition of total ignorance here) that no electrics = no pumps = no hydraulics = can't move controls because of the mechanical forces involved.