The vast majority of "drones" sold in stores are essentially radio controlled model aircraft - there are very few autonomous drones. There are quite strict rules from the CAA on how and where model aircraft can be flown. For example most people flying them in their garden will be breaking the rules on proximity to buildings.
Basic Principles | Aircraft | Operations and Safety
Article 166 of the ANO 2009 (
CAP 393: Air Navigation: The Order and the Regulations | Publications | About the CAA) includes specific regulations for small unmanned aircraft and Article 167 of the ANO 2009 includes additional regulations for small unmanned aircraft that are 'equipped to undertake any form of surveillance or data acquisition'. In summary, they prohibit unmanned aircraft from flying in congested areas, flying close to people or property, flying for aerial work purposes or flying beyond visual line of sight unless permission has been given by the CAA.
See also CAP722 Unmanned Aircraft System Operations in UK
Airspace – Guidance
CAP 722: Unmanned Aircraft System Operations in UK Airspace - Guidance | Publications | About the CAA
I think it would help if retailers of drones were required to put a summary of the CAA rules in with the product.