Battle Arena portal

As E.T. flew in the sky on a phone-like vehicle, a Battle Arena portal, with red, yellow, blue, and green flags was present on the ground behind him. (WC: Supergirl Meets E.T.)

Behind the scenes
The portal was not named in Supergirl Meets E.T., but in LEGO Dimensions, it was a portal into a Battle Arena, thus a "Battle Arena portal". No Battle Arena exists in LEGO Dimensions for the Doctor Who franchise.