The OFT have a comprehensive booklet about this.
http://www.oft.gov.uk/shared_oft/business_leaflets/general/oft698.pdfYes, it certainly includes shipping charges:
"The DSRs require you to refund any money paid by or on behalf of
the consumer in relation to the contract to the person who made the
payment. This means the full price of the goods, or deposit or prepayment
made, including the cost of delivery."
I'm not sure about the cost of shipping back to you. I was certain I'd read an OFT or similar booklet somewhere which says you DO have to pay that too but can't find it right now. I know that whilst most reputable suppliers honour the DSRs in terms of refunding the amount paid I think there are many who would expect the customer to pay for the return.
Ah here we go:
"Who pays for returning the goods if the consumer cancels
an order?
3.55 If you want the consumer to return the goods and to pay for that
return, you must make it clear in the contract and as part of the
required written information"
So as long as your contract says the customer pays for DSR returns you're ok.
As for international scope I doubt it covers outside the EU but can't say for sure. It would appear that it certainly does apply within the EU because the rules are an implementation of an EU directive.
"The DSRs implement European Council Directive (97/7/EC)7 and for
most goods and services provide additional rights to consumers
buying at a distance to encourage confidence in this method of
buying. The protection the DSRs offer is important because
consumers cannot inspect goods or services before they buy when
they shop at a distance. All member states of the European Union
(EU) must implement the Directive in their national legislation."
"One aim of the Directive is to ensure that consumers enjoy the same
minimum level of protection no matter where a supplier is based in
the EU. If you are making distance sales to consumers in other
member states you should be aware that the Directive may have
been implemented differently elsewhere in the EU. You may
therefore have to take advice to ensure that you meet your legal
obligations in other member states."
"If you sell goods or services by distance means outside the EU you
may need to take legal advice to ensure that you comply with the
legal requirements in non-EU countries"
OK, so yes to EU (but you have to abide by the local implementation lol) no to outside.
HTH