FOI - New Year's Eve Fireworks event powers

This first part of the request relates to the restriction of movement of pedestrians at the New Year's Eve fireworks show and also the New Year's celebration generally in the Westminster area.  The request is restricted to 31st of December 2018 until 12pm 1st January 2019.  The word entity should be read to include a person, persons or company.

1. What power(s) were used to restrict pedestrian traffic in the areas described above?
2. Who may exercise the powers described above? 
3. Other than the answer to question (2),  was such a power granted to non-publicly employed "entities"? 
4. What is the extent of the power that can be exercised by the entity?  
5. What penalties can be issued by the entity described above?
6. Please may I have a copy of the document that granted the above power to the entity exercising the said power
7. Who supervises the powers that are granted to entities?  What oversight is there?
8. Can I have a copy of any instructions given to the entity described above; for example - rules of engagement, operating instructions, hierarchy, alert systems and invitation to tender for such entities etc
9. What powers of enforcement can an entity use?  Specifically:
   1. what level of physical force may be used?
   2. Can an office of an entity issue fixed penalty notices?
10. Are entities required to have public liability insurance?  If yes, to what level of cover?
11. What steps are taken to ensure persons working for entities are suitably qualified? 
12. Can the above power be used to prevent a resident accessing their private dwelling or their business if to do so would involve crossing an area that fell within a controlled area ?  

These questions are more general and are not time or location restricted.:

1. How many times has the above power been used within the last 12 months within Westminster?
2. How many private law claims have arisen out of the use of such powers in Westminster?