£700k is a lot for the Bitcoin economy at the moment but I think within a year there will be enough depth to buy thousands of pounds worth of bitcoins in one location and sell them for cash in your desired location. After only a couple of weeks localbitcoins.com shows enough traders to exchange up to £1500 cash in the UK for bitcoins and then sell them in Switzerland for CHF.
If depth ever becomes significant per your prediction, bitcoin exchanges and perhaps even bitcoin transfers themselves will be regulated. £700k will have been confiscated, in cash or in bitcoins, for exactly same reasons. Don't confuse today's relative obscurity of btc with freedom from regulation.