WOW! mate that's awfull. I had a similar situation with a family member, what I did was get a court order against him so if he came whithin 20 yards of me he would be arrested, it was served to him in person by a court official so I knew he got it. Never saw him again. Not sure if you could do something similar? Hop it gets sorted.
If you use a circle as a location you can use the centre of that to pinpoint the waypoint, looking at Popey's code it looks like that is what he is trying to do using the waypoint_id but if I rememer correctly (not forgetting the senile part) these locations have a tendency to bury themselves way below the terrain which can hide the objectives waypoint text.
So yeah I normally used a marker to get the coordinates for the waypoint correct.
All this scripting talk makes it just like old times Spik@.