I'm not and was speaking generally about the process of getting cards into Wallet. So, I looked into Tesco and it appears they offer an application for the Clubcard but it does not send a card to Wallet. In that case, there are services that will allow you to make a card for Wallet.
Looking into this more to help this thread, I found an app called Make Me A Pass. It costs a bit and likely there are other options but this is to point you in the direction, the idea, of how else this might work. Other services are around but generally, the process is to install the related app and if offered, the app will make a card that is then placed into Wallet.