It's not just US, it's not just non-elites. At least the US number is free, and has long hours including weekends. The European numbers (including UK) are toll numbers, and the mainland European call centers close over the weekend!

Glad you were able to snag an upgrade, and on the more important leg, too ^! If you're not familiar with the product, WTP is not bad at all for the daytime flight.

If you don't know about the LHR arrivals lounge, it is available for you to use coming in on a long-haul J service. Shower, clothing press, breakfast, and shoulder massage is not a bad way to start the day after an overnight flight.