Novus,
You should be subject to IR35.
Read:
HM Revenue & Customs:
I think you'll be able to answer YES to most of those questions. If I were you, I'd keep a chunk of your past earnings, since the tax man can go back 7 years to claim what he thinks he's due.
You also need to be careful of VAT rules. Supplying services in excess of the VAT threshold will mean you'll be subject to that too.