Hi Martin,
Thanks for the update. That is bad luck. I think in Ron’s position I would have reported it on TNS as a possible SN noting there that it appears to be coincident with SN2010ct. If it was SN2010ct, that would mean that it was not classified correctly originally so it could have been an SN this time. It is still only a possible though so far of course until a spectrum is taken. Only 18% of possible SN submitted to TNS were confirmed last year.
I have had a look at the original confirmation CBET for SN2010ct. I must say the description of the spectrum does sound convincingly like a type II SN and not an LBV outburst.
http://ned.ipac.caltech.edu/cgi-bin/ex_refcode?refcode=2010CBET.2323A…1S
Cheers
Robin