Not drifting of topic too much, but does anyone know what a Spacies would have cost operators back in 1980, and how long it would have taken them to get a positive return on the outlay - just interested to know a little of the history there

NIB Space Invaders cost around US$800 in 1980 ish. It was put on location in a gamesroom in Reservoir. The first time an "out of order" sign was placed on this machine was because the coin box was full. This was back when it was 5 balls for 20 cents. This machine sat next to a Paragon ("the" paragon I have in my gamesroom), and there has never been a game (before or after) that came close to the earning capacity of these two games.

The first time I saw Space Invaders, I had nightmares about it !