Since you have a right of way and are interested in your own security, rather than damage their lock by supeglue, why not put a padlock of your own in the gate, so they have to ask you for access as well?
I would also suggest that you notify your local Neighbourhood Policing team that there is a problem, so if anything blows up they are aware of it and you got yours in first!
Also take up Albaqwerty's suggestion and ring your local fire station and say that you are having a problem with access and can they advise if it is likely to be a fire hazard.
Finally, if they are going to put your bin out for you pro-tem, make sure you put some very badly wrapped prawn shells, fish skin, old kippers or whatever and leave it all day at the gate.