Assessment comes first
Low muscle tone is one of the main features of PURA syndrome. GeneReviews mentions positioning and mobility devices and ankle-foot orthoses as things a child's PT/OT team may consider. Equipment is normally assessed and often provided through NHS therapy, wheelchair services and social care. Ask your therapist before buying anything privately.
Impartial information
Living Made Easy and Disabled Living give impartial information about equipment. Manufacturers such as Leckey, Firefly, Etac (R82), RMS and Sunrise Medical publish product details and often arrange demonstrations through your therapist.
Help with costs
Charities including Whizz-Kidz, Newlife, Family Fund, Caudwell Children and Variety may help, depending on eligibility. Some equipment can be bought free of VAT; see GOV.UK VAT relief.