rss feed stuck - keeps downloading same articles

[Paul Mead]

Can anyone help? I have a feed which keeps downloading the same articles
- it's only just started happening. I keep marking them as read and the
.newsrc.eld file is updated but every time I get new articles the same
ones come back as unread.

The section from .newsrc.eld which updates is:

("nnrss:Guardian - Comment is free" 3 ((1 . 748)) ((seen (1 . 601) (632. 784) 
(830 . 870)))

The second number updates each time I save in Gnus. Does anyone know
whether this looks ok, or can anyone explain what each of this number
represents? 

Thanks, Paul