It looks like you have the correct credentials to make use of PayPal Payments Pro, this includes the checkout with PayPal option as well as the pay by credit card option.
I would suggest that you make a backup of your current checkout pages, then run the wizard to create a new set of pages. When configuring the new pages select Payments Pro and you should be prompted to enter your api credentials that will be labeled like you have posted here.
If you do not see these options when selecting Payments Pro try selecting the Payments Pro US option to see if you can get to the screens that ask for the api info. As far as I know the UK and US systems work with the same api and credentials so choosing US should be ok for you. Please post back and let us know if you have any troubles with this.
