The staff travel regulations are very clear - no access when on rebate travel concessions unless in posession of a Gold or Silver card or you are 'guested' in by a Gold or Silver cardholder who is also travelling. And, Terraces only...no F lounge access even if you are Gold (or travelling with a Gold.)
Not true. Terraces access (only) permitted if travelling in staff travel J or F. Staff exec club holders permitted the usual entitlements through their card.