I was treated as an Employee.
I was paid monthly by BACS and had an employee number for payroll.
I answered yes to all of the first questions. I was only treated as an external for budgetary reasons. They had no money for a permanent headcount but had a need for a senior manager, described as a contractor, to run projects and manage a small team (4 people)
Basically they needed to employ someone to plug a gap in their team but could not wait to go through the normal process of advertising the role internally, then externally, then out to recruiters.
I had a contract, initially for 8 weeks, which was continuously extended at every review.
I would definitely consider myself as an employee and that link confirms my view.