I know exactly what you mean "chicken and egg" syndrome can`t get card because of debt in past but how can you re-build trust and credit rating without a card, most people go through a sticky patch beyond their control and it is left to computers not real people to make decisions as to grant credit.
After I was turned down by about 4 card companies I decided to approach one of them direct over the phone so at least I could give my side of the story and even though they had my "missed payments" up on their screen I convinced them to take me on with a small limit with a high APR and if I didn`t pay off the balance each month they would be getting a high return on a small outlay or "gamble".
I didn`t owe Barclaycard any money as you do, so it might be better to find a different card and try the personal touch, because every computer will kick you out as they did with me and now I am on the way to getting my rating improved.
Hope this helps
Kevin