Hi Christina
There are a number of BenefitsandWork guides relating to specific health conditions and PIP but unfortunately not on the subject of Ataxia.
The best I can do though as there are some similarities with MS is signpost you to the MS Society guide below to claiming PIP.
www.mssociety.org.uk/sites/default/files...%20web%20version.pdf David
Nothing on this board constitutes legal advice - always consult a professional about specific problems