Ok, I have now managed to relist the item & get the credit back. Seems that it's true that you can ONLY use 1 claim and once that gets declined, you have to contact ebay directly. I used the Live Chat & was on there for about an hour after getting pushed around to different people. But it was the only method I could use to get my credit back.
So a word of warning, because I went down this route. The OP "doesn't" get black marked by ebay & still has the chance to give you a feedback. One thing I'm not sure about though, is if they can still try to buy it as it still shows that I'm waiting for 1 item to be paid for.
So basically if I had just waited the 4 days & used the online non-payer. The OP would have gotten a black mark & feedback would have been blocked. So at least I will know for next time if this happens again. Fingers crossed it wont :S
Thanks all for all your advise