Yes, it seems as if they are trying to do a Paper Based Review but it will depend on what your GP writes, I would contact your surgery to see whether your GP wants to see it to help them complete the form.
If you receive Income Related ESA then you can have savings and assets up to £6000 without it affecting your ESA payments, if you only receive Contribution Based ESA then there is no limit.
Gordon
Nothing on this board constitutes legal advice - always consult a professional about specific problems