I actually registered with this forum simply to post this response as I share in your frustration with EE Technical Support. If by now you have not found a solution to the problem, I have found a way to get the VPN working by editing a simple setting on the brightbox router.
1) Log in to the router at 192.168.1.1 and enter your username (admin) and password (supplied by EE).
2) Go to advanced set-up and press accept.
3) Click on Firewall and then Intrusion Detection.
4) At the bottom, under Intrusion Detection Feature, click disable.
5) Save settings.
The problem is that the intrusion detection feature ignores ping requests from outside servers. This prevents VPN tunnelling as the protocols (PPTP, IPSec, SSTP etc) require co-operation between the destination server and your router.
Edit: It may be you also need to disable the SPI and Anti-Dos firewall protection on the Intrusion Detection page too. I simpy disabled both for a guaranteed fix but you may want to try the above first before trying this option.
I hope this helps!!!
Edited by matt555 (Mon 11-Feb-13 19:36:19)