Anna,
It's not written anywhere that you have to start with plates on the barbell! I also remember someone here giving very wise advice on how she was able to train herself to do crazy 8's with the weight that Cathe uses. She said that no matter what weight Cathe used with her barbell or dumbbell, she would do all of her bicep work with dumbbells only. She would use the heaviest weight she could, with good form and increase the weight by a pound or two every couple of weeks. I'm so sorry that I don't remember who posted this because I followed the advice and it really helped me and I'd like to give her credit for it. I remember when I first got my barbell and tried to lift 35# over my head to my shoulders for the squats on Slow & Heavy and I almost fell on the floor! In the end, I hoisted one end up on the sofa, got the other end on my shoulder then sort of squatted down and put the other end on. Not one of my more dignified moments! I don't remember how I got it off, either! I would take satisfaction in knowing that you have the barbell waiting for you and take another few weeks to use the heaviest you can with your dumbbells. Make sure you're getting enough quality protein (lots of tofu, try protein shakes if you can get them in the UK) and try to lift your barbell again without any plates on it. It's unbelievable the difference those little 5 pound plates can make! Also, I'm remembering now that you just got Power Hour so if you want to try your new barbell with that then DEFINITELY do it without plates. That is one very tough workout. Again, don't be discouraged! I promise you that you will progress very quickly.
On a completely unrelated topic - what's the status of your search for the perfect mascara? I just bought one by Bourjois and it's fantastic. I got mine at Sephora, but maybe they sell it somewhere else. I also heard that Laura Mercier makes a good one but I haven't tried it.
Good luck with the barbell and keep us posted! Take care, Linda