Katie,
This is my third time on this diet, on the first occasion I gave up because I could not manage to drink the tea or coffee without milk. I don't take sweetners in my coffee and tea. On the second occassion I attempted the diet sticking to it rigidly, but put a tiny amount of skimmed milk in my tea and coffee. I knew the worse it could do would be to take me out of ketosis and make me hungry, but I had to try it. Thankfully it did neither and I did manage to loose weight. I had to come off the diet, after loosing 1 and a half stone, as we had a family tragedy. I am back on the diet again, and this time determined to see it through to the end, and get to my target weight and keep it off, but again I just could not do this diet without a small touch of skimmed milk in my tea and coffee, it is the only thing I look forward to in my day, as unlike most other people I do not like the shakes and just get them down as quick as possible, but have a relaxing tea or coffee afterwards, my treat after the shakes. I am still in ketosis, not hungry (that was after the first 3 days), still drink 3 litres of water, and my required shakes, and I have average weight losses.
I do agree with everyone that you should not cheat on this diet, and I do not pick or cheat in any other way, but know I could not do this diet without the tiniest drop of skimmed milk in my tea and coffee. Try your best and see if you can manage your tea and coffee without any milk, if not try the tiniest drop of skimmed milk, but be aware that everyone reacts differently, so you would need to monitor yourself.