In addition to discounted coach awards to Sydney, United is offering coach awards between the U.S. and London for 35,000 miles for travel through March 31.

The text of the offer says

You must book your award ticket online only.

However, the terms and conditions of the offer say

You may purchase the reduced award through united.com or through United Reservations (call 1-800-UNITED1). The $15 booking fee is waived.

Either way, it appears as though awards are still pricing at 50,000 miles even though the promo should have gone into effect February 1.

Flyertalk.com discussion of the offer is here.