Starter hesitation

98 Discovery with 300tdi, formerly v8. I turn starter and often, not always, there is a couple or three second hesitation before the starter turns and the engine starts.
I have done some checking and the hesitation seems to be that the starter signal going to the solenoid from the switch hesitates. i.e. as soon as the solenoid gets power, it operates. Is this a bad starter switch or is there some other logic that causes this? It has been doing this for 3 or 4 years, essentially unchanged and I had thought the solenoid was faulty but recent checks show that its not.
Any ideas or experiences ? Thanks

Did you ever sort this, as mines exactly the same!

No I never did sort it. I made doubly sure that the starter solenoid works fine and it does, just as soon as it gets power. I even took it out and cleaned the sliding part. Somehow or other, turning the key does not power up the solenoid instantaneously. I think there is a relay in the circuit somewhere and perhaps this relay has some circuitry that causes the hesitation somehow.