Might depend on the binnacle, but you can get mounting kits for most Whitlock binnacles from Lewmar.
As an alternative, Edson sell some very neat cast brackets which just screw on the bottom of the table, then slide down on to the guardrail. You can't fold the table down, but I find this is often tricky with a few people in the cockpit, and I prefer to remove it altogether when it's not needed. I've used these brackets on a previous boat and was very pleased with them. Look at item 859-2 on this catalogue page for details of these and other bits of hardware for cockpit tables. You can order parts from Edson in the UK.
Re: where can i buy whitlock cockpit table fixings ?
I'm in the same process of making my own table, and needed to find some fittings. Found some at boat show from Timage & Co Ltd., who are at Braintree, Essex tel 01376 343087. They do a table bracket on page F42 of their catalogue no.9 part no. is T403.