One of the challenges of a holiday course or 'one-off' workshop is that, for a subject like Maths Methods the key to success lies in being able to consistently work on your Maths development and so it's actually probably not in your end-state performance's best interest to go for solely a one-day option since retention rates from a one-day workshop is often quite a bit lower than weekly classes, for example.
After mentoring 20+ top performers in the past 5 years, what i've noticed is that holiday workshops are
perfect for students looking for it as a supplementary option (i.e. they're using it as an overlay on top of existing interventions to help improve performance, or those who already study the course regularly but are looking at building in additional insights and strategies to help gain an edge). The critical element of success in Methods (and in general) is consistency, which is something you don't get from a holiday workshop.
If you're looking to excel in Maths Methods i'd highly recommend for you to build in consistent study habits and adopt best-practice approaches to supplement your learning