Just a quick reminder for sellers that if you accept Paypal then you ARE responsible for items after posting, so putting a disclaimer in your description saying that you are not is pointless.  If a buyer tells Paypal that they have not received an item, and you can't prove otherwise, Paypal will refund the buyer's money and take it back out of your account. 

A certificate of posting is not proof of delivery, so to protect yourself always insist on using recorded delivery or other trackable service, especially when the buyer pays you by Paypal.

2nd class recorded is usually comparable in price to 1st class standard.