This isn't a straightforward question / answer.
Firstly, changing the name of the relationship from "employee" to "subcontractor" doesn't mean you aren't in fact an employee anymore.
Assuming you would in fact legally / for tax purposes be a subcontractor, then if he is terminating the employment relationship then that would be a redundancy, so I would expect you'd be entitled to your statutory redundancy (not my area of expertise, so we'll wait and see if anyone has a more expert view).