Carol is quite right to say that getting a statement in place early is a big advantage.
You can also read some helpful comments about statements under the topic "Understanding my sons needs".
In NN's experience, provision of VI support services in schools is patchy across the UK. If you're lucky, you will get brilliant help and support. Certainly most of the VI support staff, teachers, LSAs etc I meet are fantastic and very dedicated people.
At the other end of the spectrum, we've heard about areas with next to no provision -- or in exceptional cases -- staff who are disinterested and ill-informed about nystagmus. Fortunately, those cases are rare, but there's no denying that they exist.