Great find! Definitely some kind of polypore, (possibly part of either the Fomes or Phellinus genus?).
Examples:
https://www.mushroomexpert.com/fomes_fomentarius.html
https://en.wikipedia.org/wiki/Phellinus
If you are interested in identifying mushrooms, I would suggest checking out mushroomexpert.com, first-nature.com, and mushroomobserver.org for online resources. Also, I would also STRONGLY suggest that you do not eat anything straight from the field right away. There are many look alike species of fungi that sometimes can only be differentiated using microscopic, chemical, or even DNA analysis. Don't accidentally poison yourself!
Also, if you live in North America and want a resource to carry around with you on your walks, there was a new edition of the Peterson Field Guide to Mushrooms released just this year. The Fungi Lovers community may be able to help more too. Either way, happy hunting!
Thank you for this useful info and for taking a look at what it could be. I think the Fomes is similar looking but there are some characteristic differences.
I am in the UK, I will check out the guide though as I have family across the pond. xx
Thank you xx
You're welcome! I hope the guide helps some.