I plan to start selling Bitcoins cash in hand in the future. And I'm also in the UK myself so it wouldn't be hard for me to travel to London. This is for later though when I have plenty of Bitcoins to sell

About altcoins, do you accept altcoins that are not listed on the exchanges you mentioned in the OP?
PS just seen your OP, you never mentioned Bitcoins. Are you also looking to buy Bitcoins from us cash in hand?