Terminal 3 is the one you need.

Kind regards,

Olly, your editor

I got my details the other day for the Canadian Rockies & Vancouver with Alaska add on - many thanks for this. The info states that once I arrive at Heathrow I should proceed to the main terminal - help - which one is the main terminal! The flight to Canada is with Air Canada, if that's any help. Only 2 weeks to go now!

Many thanks

Anne