Hi KB
You're welcome, now let's see if I can help a bit more!
Unfortunately work visas are hard to get - believe me, I know. Unless you qualify to immigrate under one of the other Classes (eg Skilled Worker, or Entrepreneur/Investor), or if you can find a company willing to sponsor you then your only other option is to immigrate under the Family Class.
For a Skilled Worker application you need the right qualifications and it's also a slow process, CIC quotes a minimum of 27 months. For Entrepreneur/Investor you'd obviously need $$$$ which from your comments I'd guess you don't have. Finding an approved company to sponsor you will also be difficult and very slow so it's probably not an option either.
So that leaves Family Class which means either as a spouse, common-law or conjugal partner. We've already eliminated common-law and conjugal is pretty tricky as it's basically for people that legally cannot marry but have combined all their affairs as if they were. Unfortunately not being in a financial position to get married is not an acceptable reason so you'd probably get rejected if that's the only thing stopping you.
On the bright side, Family Class is generally the fastest option and in particular the London office seems pretty quick, I'm estimating about 6 months and you'd be here with the right to work. So yes, I'm saying you'd need to get married before you moved over. This would also allow you to keep working in the UK while you wait so you might be able to afford to visit each other or at least save towards your new joint future! I'll let you think about it.
Being from the UK you should be able to stay in Canada for up to 6 months as a tourist. You can apply from within Canada to extend that visa but you must do so at least 30 days before your time is up and you must show you can support yourself while you are there as
you won't be able to work. The other option is to go out and come back in for another 6 months but you can have problems at the border if you get an Immigration Officer in a bad mood. I can give you more details on that process too if you're interested.
To get the whole thing started go to the CIC website and read through the process and request the forms. Start here
http://www.cic.gc.ca/english/immigrate/sponsor/spouse-apply-how.asp
Hope that helps, feel free to keep asking questions.