A1 Open Category
Going by your answers you can fly in the UK A1 Open Category, which is the most flexible of all.
Below are the requirements your drone must meet to fly in this category along with what you 'MUST', 'MAY' and 'SHOULD' do for safe and lawful flying.
YOUR DRONE MUST...
Display a current and valid UK CAA Operator ID if it is over 100g and has a camera.
(or over 250g if it does not have a camera).
AND...
Be either:
Under 250g at the point of take off, or...
Have a UK class mark of 'UK0' or 'UK1', or...
Have an EU class mark of 'C0'.
NOTE: Until the 31st of December 2027 you may also fly a drone with an EU C1 class mark.
YOU MUST...
Hold a current and valid UK CAA Flyer ID if your drone is over 100g.
Fly within visual line of sight (VLOS) at all times.
NOT fly higher than 400ft from the nearest point of the ground.
NOT fly in a manner that recklessly or negligently endangers and person or property.
NOT fly in a manner that recklessly or negligently endangers an aircraft, or any person in an aircraft.
NOT fly in a Flight Restriction Zone (FRZ) without appropriate permission.
NOT fly over assemblies of people (an assembly is any crowd of people grouped together that cannot move quickly or easily because of others around them, regardless of how many people are in the crowd).
NOT fly too close to people as to cause a nuisance.
NOT take off and land from an area that does not allow drones.
Be able to provide a UK Police officer with your UK CAA Operator ID and Flyer ID information if requested for it by them.
YOU MAY...
Fly closer to uninvolved people (the public) than 50m provided you do so in a safe manner (remember, you must NOT put people in danger).
Fly over uninvolved people, but NOT assemblies of people (an assembly is any crowd of people grouped together that cannot move quickly or easily because of others around them, regardless of how many people are in the crowd).
Fly by means of First Person View (FPV) provided you have an observer stood with you that maintains Visual Line of Sight (VLOS) for you.
Fly in 'residential', 'recreational', 'commercial' or 'industrial' areas provided you can do so in a safe manner without trespassing.
Fly for commercial purposes, provided you hold insurance that meets EC785/2004 for the UK.
YOU SHOULD...
Still consider taking a UK Flyer ID even if your drone is under 100g, as doing so can help you understand the regulations better.
Consider taking an A2 Certificate of Competence course if you want to fly in built-up areas. It is not necessary, but it can help you learn better methods and safer practices for doing so.
Consider third party public liability insurance for recreational flying. This site recommends joining the British Drone Flyers (link in footer).