Why would they have gone in on the Type 26? We haven't used British-designed ships since the War. Besides what Britain needs and what Canada needs for their navies are vastly different. Going in on the "26" would have just seen the Royal Navy use the RCN fand then design a ship that probably would not meet Canadian needs.
Personally I believe the RCN will go with a design that's similar to the Halifax Class, but more modernized and adaptable. Since the Department of National Defence is looking for a single design that can be either a frigate or a destroyer, this would make sense. Plus given the present government's pro-Canada defence policy, and the fact that these ships are just a part of a whole 20 year shipbuilding strategy, I would imagine that they would prefer a Canadian design to anything else that could be offered.
it makes economic sence to join onto a program in its infancy, it may be a Canadian design but it will be covered with French, Dutch, German, and Swedish electronics and weapons