Yes, you can absolutely add your British Airways (BA) Executive Club membership number to your flight booking to collect Avios.
Please follow these steps:
Log into your Heidi MyBooking portal.
Click on Flight Details to find your BA reference number, labelled as the ‘e-ticket reference’.
Go to the British Airways website and sign in using that reference and your surname.
Once signed in, scroll down to the Passenger Details section.
Under each traveller’s name, you’ll see the option to ‘Add Frequent Flyer Number’ — enter your BA membership number here.
If you need any further help, please do not hesitate to contact us!