You will never stop people doing AAVA's or overtime. As you said people see the £££££ signs!!!!
Especially those on the bottom ends of the scale, someone has already stated some people in NATS are on £26000 a year. This was the system and pay scales we all voted for. Management know this, and they love the fact that they are getting a service cheaply.
Thus to get full staffing, something I want to achieve also, you need to force managements hand. Make AAVA's/ overtime extremely expensive, very attractive to staff, but will force management to recruit and validate more controllers.
Meanwhile money can be earned, to invest.... and compensate for the end of the final salary pension scheme!!!!, Its coming!!!