I really feel for you as I was in a similar situation when I was on maternity pay and told my creditors I couldn't pay them my usual full wack until I was back in work six months later. My current account and my credit card were both with the same bank, HSBC, not Barclays as in your case, but they were completely unsympathetic and ignored all of my offers of reduced payments.
CAB advised me that as they were ignoring me to stop paying them altogether. I switched bank accounts so my income was not into my HSBC account anymore as they kept taking and returning the credit card payments from my current account, and then charging me �30 a pop when I didn�t have enough in my account to pay the credit card! That soon stopped.
They never actually approached me via bailiffs, it has to be said, but I was writing to them weekly and visiting them weekly to see if there were any updates on my offers of reduced payments. Eventually they sent me their own sort of income / payment plan form that I completed and returned with my estimate of what I could afford to pay them monthly.
They responded within the week.