Originally Posted by
MSPeconomist
When and why was the flight cancelled?
How late did you arrive at your final destination of YVR compared to your originally scheduled time before the flight was cancelled?
EU261, eh?
OP: You can try asking in LHR, but they'll most likely tell you to fill out the form. I guess you could do that and wait the however-many-business-days-it-takes-them. A chargeback is your other option, and would be successful, but you'd need to have contacted the airline first and presumably gotten a response, I think.