Kirtan : Thanks I'll look into it, but from my limited knowledge I cannot get it working off-the-bat. It seems odd that I cannot get a simple mouse click working in a simpler way :(
Riley: Thanks for looking again - but I had already seen it and the writer refers to a ".click()" command from goodness knows where!
Edit: No I'm still stumped. Having spent (several) hours looking into this, there doesn't seem to be a simple "this is how you get powershell to make the mouse click" anywhere!