Club Exemption
In the UK flying instruction is a commercial activity, 'Arial Work' which requires an AOC. Other countries such as France see it differently. The UK has deemed that if the Training takes place wholly within a club and the Instructor and the student are both members then you are exempt holding an AOC.
The term club in UK law, it seems, is a very loose term and not onerous to achieve. Something like ,' an association of two or more persons who declare themselves so'. How far it goes in terms of constitution is up to the members. With the joining of JAA the CAA required for any club that trains for a Pilots licence or rating was to register with them and to comply with certain minimum standards, which are not much. A lot more if you wish to conduct an 'approved course' such as MEP courses.
Remember the Instructor is required to be a member and also the student including 'Trial flights' to exploit the exemption.. Most clubs under its constitution automatically provides membership to its instructors. Students/pilots enrol as members. Trial Flight students normally 'sign in' as temporary members for the day at least and the charge is deemed to be included in the trial flight cost.
The pilot logs the flight 'chock to chock' and instruction from when it commences to when it ends, in most case the two will be the same. Not in the case of a 'ferry flight'.
When a licenced aerodrome is unable to meet its licencing standard then the licence is not valid until it does. Flights requiring a Licenced aerodrome cannot operate during that period.
The CAA, it would seem, show a high degree of tolerance and are not pro-active with regard to ferry flights. BUT, it would only need a party to complain and they will have no choice but to act. I do not know of any CAA proscecutions having taken place.