Originally Posted by
Captain Schmidt
There is definitely no airside connection possible at LGW - you will need to cross the UK border on arrival, and then clear security to go back airside (obviously there are no physical border checks exiting the UK).
No need for check in to open though if you have a boarding pass (as long as any checked baggage is checked through).
Lounge access definitely not available on the basis of the Croatia flight, if it is available it would be on the basis on arriving on an eligible BA flight, which I am unsure about. But make sure you keep
your inbound boarding pass if you want to try.