How do I find my British Airways Executive Club account?
Edited
You'll find your British Airways Executive Club Membership number within any emails you have received from "British Airways Executive Club".
You can also find the membership number when you log in to www.ba.com or your BA app under "My Account". You can find more support here as Roam are unable to assist with queries relating to your account, the number, or the security requirements of your BA account. (https://www.britishairways.com/travel/loghlp/public/en_gb)