I was the other player involved in these experiment.
We appear to have identified two separate issues.
1. The first one is The Brit's unability to host a game despite the port forwarding on his router being configured the same way as mine.
2. The speed issue. It should probably be pointed out that the game did not lag for me (the host). We are currently planning to experiment a bit more with the speed settings to see what effect they have. Does the speed settings effect both the host and the client? If htey effect both do they need to be set to the same value for both host and client?
