Hello!
So further to this report, which became outdated because I upgraded my project to UE 4.8, I have had this crash again. The log is here, but seems to be curtailed. Here is the contents of the crash report window. I’m going to take a copy of my project at this point and zip it up - if you’d like it (along with instructions of how to attempt a repro!) please let me know, and I’ll pm you the link 
For the record, the reason I think it might be something to do with the widget component is both the call stack, and also because I started getting this crash after starting to use widget components (although other things may have also changed in the project!)