I'm putting in a heating system for someone and have taken floorboards .one of there cats has got under the floor It has until 16.30 to get out or it stays for the weekend.I might try the Hoover on it .
Put some cat food by the hole to get out and, I kid you not, get a hairdryer on warm setting and blow it down the hole...
done that and had to be called back i found they tend to come out a bit quick if you take the board back up and bang on the floor behind them, just make sure there is no fancy china on the exit route
In old houses in the east end of London they often find dead cats walled up within them when doing refurbishments - apparently it was supposed to bring good luck. So just seal it in and bask in trouble free motoring.
many years ago a Chinese restaurant near us closed and was being done up as a night club. the builders found a mummified cat under the floor boards on a silver tray. it was left on a shed roof for ages before it was moved. was it a sacrifice or a bizarre main course somebody sent back. who knows...