There are now 4 oneworld lounges in LHR T3, 3 of which have First class sections. BA, CX, AA and QF.
All 4 lounges are near each other, with the CX and QF lounges by the entrance to the Gate 1-11 concourse, and the BA and AA lounges by the entrance to the Gate 13-22 concourse.
Heathrow Hubmaps
The T3 A380 gates are 1, 3, 5, 7 and 42
These are the oneworld T3 departures (based on today's schedule, not all flights are daily):
BA472 0615
AY1340 0730
BA478 0745
AA87 0840
BA207 0905
JL42 0930
AA733 0945
AA737 0955
AA51 1010
AA101 1015
BA474 1015
AY1332 1020
AA173 1035
AA39 1105
BA794 1105
CX252 1120
AA109 1140
BA219 1140
AA47 1150
QF10 1155
AA81 1210
BA271 1215
AA57 1235
UL506 1235
AA135 1310
AA731 1330
AY1334 1335
AA79 1410
BA209 1415
AA729 1435
BA289 1435
AA105 1445
BA275 1550
RJ112 1605
AY1336 1610
AA91 1705
AA107 1715
CX238 1715
BA85 1730
CX250 1800
AY1338 1805
BA798 1815
JL44 1900
AY1342 1925
AA141 1925
JJ8085 2010
CX256 2035
UL504 2040
QF2 2045
CX254 2205
Plus BA flights to Bilbao, Budapest, Gibraltar, Hanover, Lisbon, Luxembourg, Lyon, Marseille, Prague, Rotterdam, Vienna, Warsaw, Accra, Cape Town and Nairobi