Hi Efja_Joan, although no oral history to help you with, there are quite a few threads on this forum which mention St Pauls Square (I didn't put the ' in the search box) at the top right hand corner of the page. There may be something there or someone to contact.
I worked in Cox Street in the 1970's and have always had a soft spot for the area.
I also remember that there is the grave of a policeman who was killed on duty. If I remember correctly, if you stand at the back of the church with your back to the wall the grave is towards the road. It was legible recently so it should still be OK. I'm sure someone else will remember the story.
My friend grew up very near to the church and the graveyard was their playground. This was before it was cleared up.
Good luck with your project,