Reddit mentions of Strong: Nine Workout Programs for Women to Burn Fat, Boost Metabolism, and Build Strength for Life

I assume the personal trainer has you do weights? You're very active but I see no dedicated weight training sessions.

"Toning" is simply stripping fat from your body to reveal the muscle beneath the surface; if there's no muscle to show off, there's no toning. Strength training will not also help you tone, it'll increase your metabolism, help your body burn more fat compared to not weight training, protect you against osteoporosis, give you more energy and tons more.

If I was you, I'd do at least 3 weight focused sessions a week and cut back on the HIIT and intervals. IE

• Weight training x 3 per week
  
• Horse riding x 2 per week
  
• Yoga class x 1-2 per week
  
• HIIT/Interval Runs x 1-2 per week
  
  There's all sorts of routines to follow. For females I typically recommend
  
  Strong Curves
  
  or
  
  The New Rules of Lifting Series specifically The New Rules of Lifting for Women: Lift Like a Man, Look Like a Goddess
  
  or
  
  Strong: Nine Workout Programs for Women to Burn Fat, Boost Metabolism, and Build Strength for Life
  
  The other side is diet. Just like weight training should be the meat and potatoes of your training regimen, well, meat should be the main focus of your diet. Or at least protein - you need a lot more protein in your diet.
  
  Protein supports lean muscle growth, which, as I mentioned, is needed to tone. Increased protein intake will also help your body preferentially burn fat, it will speed up your metabolism, protein "costs" a lot of energy to break down protein (if you eat 100 calories of sugar, 99 calories of that sugar will be turned into fuel for the body; if you eat 100 calories of chicken, only 70 calories will actually be converted and the other 30 calories will be "burned" while the body processes and breaks down the chicken into a usable fuel source), it gives you more energy, helps boost your immune system and more
  
  https://www.precisionnutrition.com/will-a-high-protein-diet-harm-your-health
  
  In short, lift weights, eat more protein