What are you waiting for? If you still have the green residency card, and you are a British citizen then switch it for TIE card, it’s not law (yet) but a good idea!
source
Do I need to switch my green residency document for a TIE before June?
What are you waiting for? If you still have the green residency card, and you are a British citizen then switch it for TIE card, it’s not law (yet) but a good idea!
source