Thank you so much for your response, it has put my mind at ease. Just another quick question - because I did not have my picture taken by the security guard, will they use a still CCTV footage of my face to log that I am banned? When I was in the back room with the man, he showed me a book full of banned peoples' faces (very briefly) that looked to have been taken on a professional camera, not from CCTV.
I have most definitely learnt from my mistake and will not shoplift again.