This is just a suggestion, as I don't know what dates will work for you, but try going through DFW to LGW on the outbound:

Price Per Person 461.10 USD Passengers 1 Total Price 461.10 USD (after the discount code, the price is $435 )



Carrier Flight
Number Departing Arriving Aircraft
Type AAdvantage
Base Miles
Earned Flight
Details
City Date & Time City Date & Time


AMERICAN AIRLINES
OPERATED BY AMERICAN EAGLE 4247 ROC Rochester 12/03/2003 10:48 AM ORD Chicago 12/03/2003 11:34 AM ER4 528


AMERICAN AIRLINES
2329 ORD Chicago 12/03/2003 01:30 PM DFW Dallas/ Fort Worth 12/03/2003 04:11 PM S80 802



AMERICAN AIRLINES
78 DFW Dallas/ Fort Worth 12/03/2003 07:10 PM LGW London 12/04/2003 09:50 AM 777 4771



AMERICAN AIRLINES
55 MAN Manchester 12/10/2003 10:30 AM ORD Chicago 12/10/2003 12:50 PM 763 3826


AMERICAN AIRLINES
OPERATED BY AMERICAN EAGLE 4241 ORD Chicago 12/10/2003 03:34 PM ROC Rochester 12/10/2003 06:13 PM ER4 528


You get over 10K qualifying miles (5K qualifying points) and since it's booked on AA.com, you get 1000 bonus miles.

Good luck!