Bolty McB:
Will the gear still retract? (I am guessing here) As boeing may have proved that its safer to takoff go around and land in this config??
To my knowledge, the gear will still retract. The manuals are a bit vague, but barring a hydraulic malfunction or door sequencing problem the only thing that will stop the gear retracting is the landing gear lever lock solenoid failing to release. As far as I can tell, the landing gear lever lock solenoid is controlled by air/ground sensing, nothing else.
Even if the gear lever is stuck down, the QRH only says to push the override switch and move the gear lever to up. It says nothing about checking for other gear malfunctions, unlike the 744, where the override switch shouldn't be pushed in the event of a GEAR TILT or BODY GEAR STEERING message. I'm no expert, but it sounds to me that Boeing don't think there's a problem raising the 777 gear with the main gear steering unlocked. There's nothing in the SB or Ops Bulletins that would suggest otherwise.
BGQ:
You wouldn't get a master caution light or aural warning for the park brake at V1 -10. The Master caution lights, aural warning and advisory messages are inhibited from 80kts to 400 ft or 20 secs after rotation.
Perhaps it's different on your aircraft, but on ours the master CAUTION lights & beeper are inhibited from 80 knots to 800 ft RA, or 30 secs after lift-off. The master WARNING lights & bell on the other hand, are inhibited from V1 until 400 ft RA or 25 secs after the inhibit began. The take-off config WARNING (which is triggered by a number of conditions, including parking brake set) is not inhibited until V1.