quick visa question

Hi, just had a quick question that has been bugging me and I'm having trouble looking up.

I'm a British citizen, hold a valid passport, and have made a fair few trips to Canada to see my gf. (I think last time, I was stamped for 6 months as I went through a short interview at passport control, and at the outcome after phoning my gf to double check everything, the stamp had "V - 5APR2008" written underneath).

If I wanted to enter the country to marry my gf, I understand the process that would follow with regards to paperwork for immigration, but would I need a visa of any sort to enter the country for that purpose? Or, do I just fly in, say I intend to marry when I'm asked why I'm visiting, go through the usual questioning/information double check with my gf, and they let me in? (I would probably need to come back home first for a few things for a little bit, so I wouldnt be entering without intention to leave)

I've been looking on the official website, and nothing is mentioned about needing a visa before hand to enter for marriage.

Just wanted to double check if I'd need anything beyond my passport to get in so we can actually marry.

Thanks for any help.