Thank you for the fast response. I did order on a guest account. As I forgot to log in, unfortunately.
I have tried the email method of checking the keys associated with my email address and all I got was my key to Start 10.
And there is nothing in my account history that shows the purchase.
But I have checked with my bank. And I have been charged £3.99 for the upgrade key for Start 11. Shown as FS *STARDOCK AMSTERDAM NL. on my account.