there is clearly a mismatch here, I was with the group that read off 249 on the 20th January and I can confirm it was only the MSN that was read off but it was read off each piece to be certain that is was all the same frame. I did not read it off myself but I trust the person that did. I was back in TLS on 24th Feb and there was a UAE frame in Body join that we could not identify. I suspect it is a "mispole" on the XFW log
I still think it was MSN 245 on Convoy 1 2017. Reading off parts in XFW in a hanger close up is easier, so I think MSN 249 was still in XFW then.
Edit - We should only have about 6 weeks to wait and we see what MSN gets rolled out !