Removing Credit card info on checkout page

As you have told me, sagepay doesn't allow me to make payment and remain within my website. To check out, I have to complete credit card details on the checkout page in order to validate the page and then continue to pay, but I currently have to visit sagepays website and complete credit card details for a second time on their servers to get a successful order... this is a bit annoying and cumbersome for customers, so I was hoping that I could remove the card details for convenience to the customer.

I'd like to remove the card details allowing the customer to complete them only once on sagepays servers rather than on both.

I have removed spry validation for the card fields in the checkout page, and this seems to be working fine, but the page fails to validate and I think this is due to code in the checkout_form.js on lines 72 to 115. Do I remove this code so checkout_form.php validates, or is there other code that needs to be removed.

Thanks.

Mat