A user was setup to connect to his Small Business Server by PPTP VPN for file access. This was working all round the world, but when he came back home it stopped connecting. The user was on Virgin Media, however I knew from other users that Virgin ISP did not block this on their network. After logging into the SuperHub Router on default IP 192.168.0.1 and the default credentials admin and password changeme.

I found out the PPTP Passthrough was unticketd in the Content Filtering Menu and Services Submenu. After enabling this again , he connected straight away!