Mac OS Mavericks VPN Issues

[#1]

My Mac (already on 10.9.2) is having issues connecting to a VPN.  It works fine from my office but not at home with plusnet.  The symptoms are - it makes a connection, everything is fine for about 10 seconds (it pings successfully to machines on the vpn), then then pings timeout. A minute or two later mac os drops the vpn connection completely. 
Any help anyone?

[#2]

Locked in favour of duplicate post http://community.plus.net/forum/index.php/topic,125226.0/topicseen.html