Hello vyolla.
Thank you for your reply. I didn't add any optional upgrades or have a selling duration of 3 days or less.
I will concede that I didn't know about the 300 per month limit and there is a chance that I went over this limit. My situation is that I have about 70 items that I relist once or twice a month and by choosing 'Relist' and the Ebay screen message states '£0.00 Insertion Fees' that is what I expect.
It would be good if I could be sure that Ebay have got the charges correct. Where do I go for that I wonder?