Read this: http://britishexpats.com/wiki/Spousal_Sponsorship-Canada/FAQ#What.27s_going_on_with_the_Mississauga.2FOttawa.2FLondon_situation_for_British_outland_applicants.3F
And this: http://britishexpats.com/wiki/Spousal_Sponsorship-Canada/FAQ#How_long_will_it_take.3F
And have a look at the spreadsheet linked in my signature, and read the red box on the cover page. The spreadsheet tracks applications filed through London, so gives you a more realistic idea of processing time. The average has been sitting at 8ish months give or take a bit for well over a year now.
I'm the owner of the spreadsheet, so I can happily add you. Adding your info to the spreadsheet is a great way to say thanks for the advice you receive on the board - more data on the spreadsheet helps us give others are more realistic idea of processing times, plus it helps alleviate everyone else's stress if they can see that tons of others are in the same boat.
If you want to be added, then let me know:
-Date application received in Mississauga
-Whether you applied as Married or Common-Law
-Date of sponsor approval
-Which office is processing Phase 2 of your application (will say on your sponsor approval letter/email)
-Date(s) of any other requests you've had
-Whether or not the principal applicant is non-visa exempt
-Current location of the principal applicant- closest major city is fine if you don't want to be too specific!
Post any updates over in this thread: http://www.canadavisa.com/canada-immigration-discussion-board/thread-for-outland-london-uk-applications-t49436.0.html;new#new which is sort of the 'holding pen' for applicants via London.
Hope that helps!