[Talk-GB] Help: Conflict not resolving in Potlatch 2

[Graham Stewart]

Please excuse the slight off-topic, but I've spent the morning doing
some Bing/OS_OpenData armchair mapping around Amble in Alnwick and
Potlatch is refusing to save my changes.

I get a message saying: 

  "An item you edited has been changed by another mapper. 
   Download their version and try again? 
   (The server said: Version mismatch: Provided 1420, server had: 1421
   of Relation 9579)"

If I say "Yes" then I just get the same message again (and again and
again...) until it eventually it gives up and says "HTTP error".

Does anyone have a way out of this scenario or my work lost?
I'd be happy to lose just my changes to members of that relation but
keep everything else.

I've tried pressing 'C' to close the changeset and starting a new one.
(I've also noticed that if you confirm that dialog with the return key,
rather than space, then it seems to report a new changeset ID anyway).

Thanks
Graham