I've done tons of changes to US-LHR award bookings as a 1P, so any fee waivers for 1K don't apply to my experience. You can get dinged for the close-in fee for changing just the outbound flight(s) date/time. But you don't get dinged for the close-in change fee for changing the date/time of the return flight(s).

It's unclear to me where the OP is based and whether the ORD-LHR flight is an outbound flight or a return flight.

This policy distinction between outbound and return sort of makes sense to me. It prevents the loophole where you book an award way out into the future to avoid the ticketing close-in fee, and then change the outbound flight to one within the next 7 days. I've never specifically queried as to the close-in fee is assessed if you're changing from an relatively imminent departure to one much farther out in the future.