That's a good plan b Y123. It's likely to be tricky to get an unscheduled punt at a parlour at lunchtime as it tends to be a peak time.
Good point Forrest
Maybe it helps if you have good local knowledge of certain parlours as I have in the past phoned asking if so & so was available to be told no but the receptionist has phoned said girl who popped in just to allow me to pop.
Now don't get me wrong I'm no stud I just have a fat wallet.
Also I have been known to tip the odd receptionist in the past, punters would be surprised how much of an investment that can be when you're in need of an emergency punt.