The entrance we must use for access through the Luton Hoo private estate is located at the southwest end of Park Street, via the gated entrance (Gate Code required, provided on booking).
Take care to observe the 20mph speed limit, do not drive on the grass or park by the hotel.
This link should show the route through the grounds, however you can follow the signs to Warren Weir and park in the stone car park on the left after coming down the hill.
https://maps.app.goo.gl/J7LG2tSLzwMqxhjH8
Then, track by foot through the woods to the boathouse, this can be a little muddy. One adventure already done!