Tony...look at this http://camranger.com/
Thanks, Ian, Chauncey and Colin. I will follow your suggestions although I really need a solution that does not go through another computer.
And apologies to Andy for hijacking his thread.
I am pretty certain that if you do a Google search with Canon DSLR connection to IPad you might find some information...
I had a look at the camranger.com site as suggested by Chauncey and Ian. It looks as though that would do exactly what I had in mind and they also supply a motor controlled tripod head which looks good. It also looks to me as though it would be an answer to the original question for this thread.