Hi,
Whilst the UCS seat and meal service is the same from LHR and LGW, the LGW fleet only has 14 suites in the nose and no other area,no inflight beauty therapist area and the bar only has two stools compared to 4/6 on the LHR 747 fleet.
The LGW IFE tends to be Nova ( about 10 tv channels) compared vport (AVOD) or Odessey ( 20 channels) on the LHR 747-400.
Regards
TBS