Hello and thanks for using Just Answer.
I am Al and am happy to assist you with your enquiry.
On the basis that your property is Freehold, neither the Council or anyone else can prevent you from sitting on the roof, full stop. It is only when you start to make alterations that you may be caught be planning legislation.
I hope this clarifies the position to you.
thought the purpose of this site costing me £32. was for legally binding answers
I have answered your question, in that there is nothing stopping you from sitting on the roof, once the railing has been mremoved. As a Freeholder of a property, no third party can tell you what you can and can not do in your own home, unless it breaches planning law.