While waiting for a reply, I dug deep, played around with the code and got it
Find: <p>[0-9]+</p>
Replace: Nothing
In the code view, it looks like there are line breaks in between my paragraph but in the book view those lines are not visible so I didn't have to put in anything to remove line breaks such as \n.
Not sure why the other posts were going on and on about \1 and all that. It confused me.
I apologise if I wasted your time. These may look easy peasy to many but it is a struggle for me without any programming knowledge.
Thanks!