Tried that. No difference.

Incidetnally, when connected, I can "ping" the 2860n's internal address (192.168.0.254) but nothing else. Does that help at all?

Are you trying to access other resources using \\machinename or \\192.168.0.x ?

Try 192.168.0. format bceause your DNS seems to be set to 212.159.6.10 so I wonder if you'd be able to resolve machine names.

Can you browse to http://192.168.0.254 ? That would show that traffic other than ICMP(ping) is working

I sorted the problem. The client machine (Windows 10) needed to have SmartVPN given permission to pass through the Windows Firewall. Oddly, SmartVPN install did not do that automatically despite the fact that it required an elevated UAC prompt to operate.

Thanks for everyone's help though.