I know its probably been asked before.

But I have a leylandi hedge approx 16m long and 5m tall (15ft) it has
previously been topped at about 4m.

I need to take about 1m off the top.

Any ideas how much this might cost me ??? or how long for 2 people ??

Access is very easy, as its lawn right up to the hedge. would the
person use a tower or ladder or steps ??