Corecommerce customisation

Permalink
Can anyone please tell me how i would make the following customisations or is there any documentation?

1. make the checkout default address 'United Kingdom' - been searching all over for the files for this and cant find them anywhere. Is the list a database table?

2. Make the tax price and shipping price display as subtotals on all for the checkout pages, not just the payment page.

many thanks

pixelfish