Specify deposit amount to deposit and get invoice.
Looks like this is a UK only service? You need to verify if you do more than $150 USD in vouchers. I'm not a fan of the voucher model. What makes them better than a normal exchange?
Not to mention their commissions 3-6% is a lot. If you do the KML anyway, it's cheaper to use a normal exchange.
"Our standard commission structure is detailed below:
Redeeming Vouchers
Selling Bitcoins
"
Looks like a pain to use, not many places you can buy a voucher better off using an exchange as they have better prices lower fees and higher liquidity.