For that price (£2000) i would watch my back going there, a lot of bad neighborhoods in London, if you do decide to go which i definitely don't recommend make sure you go with a friend, and For £2000 don't put your self at risk mate.
Hmm. If you do decide to go be very vareful. Go in a big group, however there are some scumbags around who would have no problem pulling a gun or a knife. If they do have the ps3's inspect the boxes and make sure you put markings on the cash. Then if they steal it alert the local constabulary who will put the word ut stolen money is doing the rounds and people will notice the mark and call the police.
It is very risky especially if they know you will turn up with a large sum of cash on you. make it clear you will not take cash with you, say you will inspect the goods and then will go to a bank and transfer the money to his account.
Make sure you meet during business hours, when banks are open so he/she will know you are able to transfer/withdraw the money.
Even so i do not recommend going, its going to be some sort of scam