The power jack is completely FUBAR. Fortunately, my housemate Rob has a trusted friend (also Rob) who works with laptops and electronics. Rob 2 determined that the job was beyond him, since it would require completely stripping the laptop to get at the plug; but, he highly recommended Abdullah on Queen's Way. "Tell him I sent you and he'll treat you well. If it's not worth fixing, he'll tell you instead of charging you a fortune." Turns out Abdullah believes he can do it under £80, barring complications, and will try to have it done for me by tomorrow.
In the meantime, I could not resist the lure of £1/75 minutes internet.