Withdrawing money on a credit card is generally a bad idea, as it will generally be charged at your 'cash' rate, which is much higher than purchase or balance transfer rates.
It's also worth pointing out that, depending on his credit rating, the OP may not actually get a 0% card. Same with low rate personal loans, they all depend on circumstances and you may not get the headline rate. The small size of the loan will also tend to mean rates will be higher.
Without knowing more about the OP's finances, a good recommendation is hard to make. Who do you owe the £1800 to, on what terms, and how can you improve it. How much money do you have coming in and out. Can you pay, for example, £200 a month, which would get that cleared in 9 months anyway, or are we looking over a longer term?