Hi I'm new to this so hope this is correct I have just grabbed secondhand cakewalks VS700 and the I/O 700R but am have big trouble getting the correct connection cable can anyone help advise me on how I might get hold of one. Many thanks.

Wrong forum. SONAR Home Studio is a Cakewalk product not a general description for posts. There is a forum for the V-Studio 700 below. The product is supported by Roland so they would be the people to contact.

Just to add, by correct connection what do you want to connect? Seems both these units are USB audio interfaces and made to work with Sonar directly. One is a control surface , and one is a audio interface. 
As far as connection them, A USB B cable to the computer. 
Did you read the manuals yet?