Hurley Weir needs no introduction as it's the most well known play spot in the South East of England [well, it was when I paddled there regularly, but that was before the Lee Valley White Water Cente was built!]. It hosts numerous competitions and some of the top rodeo paddlers paddle there. Furthermore, Hurley Weir is not operated as a commercial venture so it's totally free.
Hurley Weir is located on the River Thames just outside the village of Hurley, about 4 miles North West of Maidenhead. To get there by road, assuming you've come along the M4 get onto the M404 (Junction 8/9 of the M4) and follow it north. After a short distance this road becomes the A404. Whilst heading north, look for the exit signed 'Henley (A4130)'. Take this exit. You should now see a smaller sign for Hurley Village, follow these signs. At the first roundabout go straight on following signs for Henley and Hurley. After about 1 mile you will see a sign for Hurley village pointing to the right. Turn right, off the main road as directed by the sign and follow the road through Hurley village. At the end of this road is a small free public car park. Here's where you park and change. The car park is known for car crime so please do not leave any valuables in the car!