I want to recommend a fitness instructor here in Helensburgh, here name is Lisa Johnstone at https://personaltrainingwithlisa.co.uk/
I have done a number of her classes over the years, doing spin, step and kettlebells at Chris Bowman Fitness
The Kettlebell classes have been the best for all round body workout that has helped me in my ultra running/hiking training. The kettlebell combo combination moves are tough and testing, which really make the classes challenging and fun.
The workouts help with my strength and cardiovascular fitness and the benefits have worked on my glutes which I have a weakness.
After a few weeks of classes, I have built up my kettle weights and now feel the benefits in my downhill running.
I hope these two workout videos from Lisa will give you a taste of the workouts and that you will join the classes at Chris Bowman Fitness