As Steve say, it is diffucult to explain the road down to the beach, when using a car, as all roads there does not have any name sign! But here is what I did write in Jan 18 2011, a comment to a guest report written by Sue Smith on Nov 27 2010, regarding Arnos Vale Hotel.
If one come by car on the main road, the road down take off to the left in front of a high green area, a school area I believe. Than you turn right in front of a concrete wall wich split the road into two, after som 75m you choose left and next right again. It is difficult to explain as there are no street name, but there's peoples around beside the road. The road is OK all the way and it end with a small parking area beside the fense just 25m from the beach.
The beach is a nice place if you want to have a quiet day at the beach, but you need to bring everything with you, water, soft drinks a.s.o.