Are there any electricians out there that can advise me if doing this course with very poor maths is achievable or not?.
That is very difficult to say. When I went through my apprenticeship, there were some guys that had difficulty with math that made it through but whether your skill levels are above or below theirs is impossible to say. It surely will be a struggle for you but really, only you can say if it is attainable or not for you.
What they finally did in my area is offer a math refresher course. It was a pre-apprenticeship course that ran for about 6 weeks. All it was was a math course designed to refresh, and in some cases actually teach, the apprentices the needed math skills.
You might want to look to a community college or some other school for a course in math to help you. Trig is used a lot in our apprenticeship. Not knowing at least basic trig will cause your training to be quite arduous.