Round Two: The Unhappy in Pursuit of the Unavailable
Next attempt to get my Powerbook fixed: I talked to Apple Support, and they gave me the number for the Apple Store on Regent Street, to see if they might be able to resurrect Plan A.
Next problem: you can only get to deal with the "Genius" Bar if you have an appointment. And you can only book an appointment on-line. But you can't book an appointment for a particular day—you can only book appointments for today (unless you pay an extra £80 a year for ProCare). And when I checked the site at 9:03am and 10:30am today, it told me: "Unfortunately, there are no more reservations available today. Please check back tomorrow."
It makes booking an appointment with a GP seem positively straightforward.