Our friends used a private hire, other wise if you use railroad you have to switch , London to Reading, Reading to Southampton .coach can be unreliable due to traffic conditions on M3
It may be wise to have a test done in the US. You need a test result 3 days before embarkation .
If you aim to be in Canada any longer , pay a visit to a Shoppers drug mart and get advice from them.
You will need to pay in Canadian $
You can complete the arrive can app 3 days before embarkation, and that should then give you a QR code that's good to get off the ship in Victoria,, if you try to complete the app greater than 3 days prior it will throw your dummy out of the pram