I'm not sure about your question-
If you are asking if it makes a difference in how quickly the application is processed depending on where you get married, then my answer is it doesn't matter where you get married, as long as you have the marriage certificate and other proof of the the marriage.
If you are asking about processing times-
If you get married and stay in the UK, and submit your application from OUTSIDE Canada to Mississauga, and then to the London office, it will most likely be around 9 months before you are able to come to Canada as a Permanent Resident.
If you get married, and stay in Canada or come to Canada, and submit your application INSIDE Canada to the Case Processing Centre in Vegreville, Alberta, it will be about 6-8 months until you are able to work in Canada, and anywhere between 9 to 18 months (maybe longer, maybe shorter) because you become a Permanent Resident.
I'm not sure if that answers your question.