Firstly you don’t need a CAA license to fly at night you do need night permissions on your PfCO if you plan to fly commercially at night. The second part of your question is more about English Heritage and their rules which are far less draconian than National Trust. They require you to abide by the CAA regulations on separation and want you to get their permission and then to plan it properly like a commercial operation. Lastly they require you to do the flying when the site is closed to the public. All that is fair enough oh and they want you insured and trained. The last bit of their bylaw is probably the rub in that they will treat all drone flights as commercial and charge you. I don’t know how much which is probably why you feel they charge too much and you may well be right. In answer to what will happen to you depends where you take off from. If you take off from public land not EH land and also land there and do not set foot on the EH land there is nothing that can be done as it is perfectly legal the CAA control the airspace not the land owner. On the other hand if you sneak onto their land and operate from EH property then that is trespass you are breaking their bylaws by flying and they are at liberty to sue you. I’m my opinion you would be best served as would the drone community by gaining permission from them this way the drone community builds s working relationship with them and things will tend to improve. I am sure they are able to negotiate on fees and if it really is not commercial they may well bend. They may not either as they are drastically underfunded and mostly don’t charge for site entry so you can’t blame them for trying to raise funds for their sites. Try getting into a National Trust site for free. The main thing is don’t tarnish the Drone Flying community by doing anything illegal and getting yourself in the papers it is hard enough now to find s place to fly a drone