The secondary school cannot withdraw the place, as others have said. However, if the same behaviour is shown in secondary, they will exclude too. Most secondaries I know actually move towards exclusion quicker than primaries seem to- e.g. serious violence towards other students is usually a perm exclusion in secondary, whereas some primaries seem not to permanently exclude for this.
It's also worth bearing in mind at secondary age, other parents may get the police involved if dangerous behaviour is shown.
Therefore, I think the key is ensuring there is a successful transition to secondary, and considering whether mainstream is definitely the most appropriate option.
If she does not already have an ECHP, I would seek one.
If she does have an ECHP, as someone else said, ask for an urgent review.
Talk to the secondary about what has happened- show willingness to work with the school and they may be able to put support in place e.g. writing a safety plan. It may be that, for example, she is better off currently not doing some aspects of DT if that helps keep everyone safe in school?
Is there any way you can expedite diagnosis? Medication can be life changing for some children with ADHD. Sometimes initially seeking an ADHD diagnosis only can speed up waiting times? Or is there any possibility at all to go private?