Right here you go:
2.17 How a contract is concluded determines whether the method of sale
is an auction and so falls outside the DSRs. Fixed price sales,
including ‘buy it now’ type transactions on internet auction sites,
are covered by the DSRs because such sales are not concluded by
auction.
Can I charge the consumer the cost of insuring items that
I send out?
3.20 No. These items belong to you until they have been accepted by your
consumer. So you cannot charge your consumers for carrying risks
that you should bear. See paragraph 3.36 for more information.
3.36 Where goods are lost in transit from you to the consumer you will
need to either send new goods or offer the consumer a full refund,
including delivery charges. See paragraph 3.20 for more information
From the compliance document provided by the office of fair trading, can be found here:
http://www.oft.gov.uk/advice_and_resources/resource_base/legal/distance-selling-regulations/
For the purposes of small claims an individual is determined to be acting as a business by the frequency of sales. So if a person sells large numbers of items then they are a business.