2000 V70 SE, 289K miles, B5244S, AW-55, Denso, N/A

Follow up,

This Matthews link proved to be very helpful:
https://www.matthewsvolvosite.com/forums/viewtopic.php?t=22911&start=10

Key words in the above posting's 20 Nov 2012 comments (see also the photos):
"Drill out the small port beside the shift cable interlock (can be done in the car if you cannot release the cable), this will release a spring and a metal pin. YOU MUST REMOVE THIS PIN TO FIX THE LOCK MECANISM, as a broken slider will keep jamming it in the guillotine."

On my car's lock housing, I drilled out the cap covering this small port referred to above, and removed the hardened steel pin and spring that was jamming the entire lock mechanism.

The steering wheel lock is now non-functional (which is OK with me). Otherwise, every thing works as it should; ignition key turns freely through all positions, car starts, and shifter unlocks once car is started.

I didn't use Volvo security bolts to re-mount the lock housing to the steering column. Instead, M8 x 15mm length allen-head setscrew bolts worked satisfactorily.

For sure, saved a tow to the dealer or a trip to the locksmith.

Safety caution: Disconnect the battery before starting this work. You'll be working directly around the steering wheel airbag. When job was finished and battery reconnected, SRS functions on startup were all OK (SRS light illuminated, the system cycled, then SRS light went off).