I know a lot of students, myself included, apply directly to PhD programs after completing a 4 year bachelor's degree. I'm in the US so I'm not really sure how schools look at programs in other countries, but I know grad schools accept a lot of students from a lot of different backgrounds, so I'm sure there are others in your position. It's possible there might be someone with similar credentials to you in the admissions results for 20xx threads on here. Definitely take the math subject area gre though! I'm sorry I can't be of much help!
Best of luck in your math career