That sounds to me like you're covered by EU261. Several legal cases in various countries have established that it's the arrival time at final destination that counts for delay calculations. That said, I don't know if one of those cases was taken in the Irish Republic or against Air Canada. I don't think either applies so I reckon you're going to find that Air Canada might take the view that they delivered you to Vancouver on time so tough! Because the flight commenced in the EU I don't know whether a UK based dispute resolution service will be interested; you probably need to find the equivalent for the Irish Republic. It's possible that one of the UK based legal companies that specialise in this area might be prepared to take it on but, again, I suspect you may need an Irish based company.
Solicitor might help