I don't want to sound negative, be beware of any seller purporting to be in London (or anywhere in the UK for that matter) whose advert is in BAD English.
I have just purchased a DS Lite Charger from someone for the princly sum of £3.04 including postage - I know cheap but hey I stupidly won the auction. The power seller had a relatively good feedback, but again unfortunately I didn't go past the last 100 feedbacks. I paid immediately and patiently sat back and waited for the charger to arrive. Two weeks later it arrived - FROM HONG KONG. The package included - wait for it an envelope so needless to say the charger was broken. I would never have bought the item from Hong Kong or China if I had known.
I started communication with the seller who asked me to send it tracked to China! I told him that I wouldn't pay the £2.99 to China until I received payment and he insisted it had to go back to China, offered me a partial refund of 50% less postage (bearing in mind the winning bid was £0.99) - not enough to send it back to a UK address let alone tracked to China.
I know it is down to the buyer to return the item at their own cost should the need arise. But a seller who lies about their location seems to get away with the lie and lack of postal protection, leaving the buyer to foot the cost of sending the broken item to the seller's real location. I dont know where to turn next. I have reported this to both e-bay and to Paypal who have told me that until the charger is returned, the refund will not be given. However to return the item it will cost me more than I paid for it (including the postage).
I hope none of you ever have to go through this with a Seller lying about their location to sell more, but if you do see something where the wording is a little suspect, please ask them where the item is located before you buy it.