I should imagine it will be a profitable venture for them if their markup is £50 over what's available elsewhere. At the time of writing, they're quoting £297 for 1 BTC, but I'm seeing £247 and under on LocalBitcoins. Convenience is always tempting because I'm quite lazy, plus it avoids bank transfer fees, but it's still a bit steep.
Perhaps I was a little harsh on them at first, the difference between them and LocalBitcoins.com now is only ~£35, so I guess it fluctuates a bit over time. That seems more reasonable for avoiding the hassle of finding someone with a compatible payment method and sending off photo ID. Might consider them in future if I hear any good feedback.
