If you have not yet created a VPN login through the UK2.NET Dashboard, you can do so by following the steps here.
Note that these instructions are for L2TP VPN accounts. If you have an PPTP VPN account, instructions are available here.
You can set up a L2TP VPN account in OS X as follows:
1. Open System Preferences.
2. Select Network under Internet & Wireless.
3. Add a new network by selecting "+" below the network list.
4. Under Interface, select VPN.
5. Under VPN Type, select L2TP over IPsec.
6. Set Service Name as you see fit. “UK2.NET VPN” may be appropriate .
7. Click “Create”.
8. Set Server Address and Account Name to match the user name and server shown in the UK2.NET Dashboard.
9. Click “Authentication Settings…”
10. Select Password for User Authentication and Shared Secret for Machine Authentication. Fill in the password, and for Shared Secret use the pre-shared key under “PSK (L2TP only)” in the VPNHQ section of the UK2.NET Dashboard. Click OK.
11. Click “Advanced…”
12. Make sure "Send all traffic over VPN connection" is checked, and click OK.
13. From the gear drop-down under the network list, select “Set Service Order…”
14. Drag and drop the services to ensure that your VPN connection is at the top of the Service Order list, and click OK.