Thank you all for your views I found them most valuable, in particular I liked the posting of Totalise, which took it to another dimension though I'm still not convinced my opponent was playing at such a level.
Personally I felt the shove was a sign of weakness if it had been made by one of the many regular donks I would have inst-called. For the record I did call and my opponent showed

and the river was a blank. I still think it was the right decision with the info available at the time.