This is a Louis Marx Lumar 99 Competition yo-yo- the type used by the Fourth Doctor, certainly from Genesis onwards:
Requiring reliable, quality yo-yos, BBC Enterprises sent Philip Hinchcliffe some Lumars to test.
They sent them to the wrong Phil Hinchcliffe:
When the correct Philip Hinchcliffe eventually got them, he sent back an equally tongue-in-cheek reply:

