Okay, reading the further comments,
I think its best to put the "how to burn more body fat" aside and come to the conclusion on which why you think you should be trying to lose body fat,
Apart from what the scales say, is there any other reason why you want to reduce body fat? to look thinner? to look leaner?
I would ignore what the scales say if you are happy with how you look and if you genuinely think there is no cause for concern in regards to your health.
20-22% Body fat is not bad at all, probably average if not less than average? Especially the older you are. If you think 20% of my body is fat, that might sound pretty bad, but in reality, its not, the NHS should be able to provide you with an ideal body fat percentage range for someone of your age and gender. Reducing your body fat percentage too much will do more harm than good.