Curse of the Chicken

Experts are welcome to comment.

I think it's yellow chicken fungus attacking this tree. The tree is in the grounds of a stately home, so might be a Pin Cherry (?), not native of the UK. Both details courtesy of Google lens. I DO know it's in Avington Park near Winchester so some local knowledge might help.

The colours happen to catch my eye as I cycled up a hill, but they were worth losing my momentum for. Size, 30 to 45cm across. 

Thanks for hosting,  Marlieske