Walter
For 14 (that is fourteen) YEARS I operated into and out of RAF Northolt on an almost daily basis - often more than once a day - and on the way into RAF Northolt we utilised exactly the same beacons that we would have used were we landing at Heathrow - with the exception of the ILS. We were using those beacons as en - route navigation aids.
From observing our visual approaches down the Northwest corridor into Northolt you could have been forgiven for assuming that it was our intention to land at the small airfield at Denham.
The fact that there was a landing strip in the vicinity of the Chinook's planned route does not repeat not signify an intention to land at that strip.