I had found a very detailed set of instructions (copied below) about the owls location, and indeed they were just that. About 3 or 4 minutes walk into the park and I found the bench and the tree. I also found 3 other borders all staring up a a gorgeous tawny owl snoozing in the late afternoon sun. This is a really bad iphone photo. Can you spot the owl!!!! I've given you a clue.
If anyone has a chance you should get a really good view and a good photo if the sun is out. I'll certainly be going back with my big lens.
go to the path that runs north-south between the Speke obelisk and the statue of Physical Energy. Exactly halfway between these landmarks there is a bench on the west side of the path. Stand on the path in front of the bench, at the right end of the bench as you face it. Look west at right angles to the path. Very slightly to the right of this line is a big horse chestnut tree with a broken top that is visible through the branches. This is the owls' nest tree. Between the path and the nest tree, slightly to the south of the bench, is a crooked line of four horse chestnut trees roughly parallel to the path. The owls and owlets are likely to be in either the nest tree or on the middle two of the line of four trees.