Thanks for the replies much appreciated.
The booking was made online direct with AC from the UK, routing DUB/YVR/YCD. Whilst outbound leg in flight from DUB to YVR we received a text saying the next sector YVR/YCD was cancelled but we were rebooked on a flight the following day. On landing we checked at the International desk and they issued refreshment vouchers and said go upstairs and you will be sorted out with Hotac at the domestic desk. All that would have been fine and I would not be making a claim. These things happen.
On getting "upstairs" incredibly they TOOK AWAY the refreshment vouchers and flatly REFUSED to issue any Hotac with no rational explanation and the duty officer would not speak to me.
They eventually put us on a later flight the same day which itself was delayed over 5 hours until 0050 the next morning which meant we had spent over 10 hours in YVR for a 15 minute flight.
We were travelling business class!!!!
On the way back our luggage was lost, eventually it turned up bruised and battered a few weeks later. I have not made any claim for that.
AC have offered a goodwill voucher for use against any future full price booking, I did email them to say this was not acceptable two months ago and have had no acknowledgement of receipt.
I think I may have a case?