Yes. It is a fossil coral.
Corals are one of the fossil types that Whitley Bay is known for. Have a look at this re Seaton Sluice (the N. end of the bay) - http://www.seatonsluice.ukfossils.co.uk/
Sadly not. This is how it looks when it's wet (as it was when I spotted it, else I probably wouldn't have noticed it!)
On that note though I am wondering if anyone has any tips on how it could be polished to look like this all the time?
My daughter has a rock tumbler but I don't know if that would destroy it.
To put the fossil in a rock tumbler it's best to have more material of a similar density because specimens that are harder or softer will wear our at a different rate.
I have used neutral shoe polish to bring out the features in a specimen, I warm the fossil up then rub the polish into it.
Don't try to polish it (make it shine) until you see the result of letting the neutral shoe polish soak into the your find.