VAT is normally zero-rated on all Adapted Therapy Tricycles for people with disabilities or a chronic illness. Please complete the exception form when completing your purchase.
If however, you are not registered with a disability and are merely seeking a tricycle for more stability, then you will have to pay VAT. (i.e. If you don't need any supports, and or adapted foot pedals, then it's not an adapted trike and thus not zero-rated for VAT)