Completely lost VPN access, any ideas

[#1]

Any ideas, I first noticed this yesterday when trying out a new home router but I've swapped back and its still acting like the site's just not there anymore.
I went into work thinking I'd find the whole thing crashed or worse but at work its working normally. I was a bit too busy to try a dial-up test to see if inbound access worked, but if I remember I'll try it tomorrow.
I'm just wondering if there are any changes at plusnet that could account for it, like if the work account was moved to a pool IP?
Then again maybe the router at work just isn't playing ball? Its not even ping-able but DNS appears to still resolve.

[#2]

Hi oliverb,
I can see that one of our agents has looked at this for you this morning, I hope that's fixed things for you. Please let us know if not and I'll be glad to take a look for you.

[#3]

Yes things seem to have come back to life. I think I had some grief with misconfigured IPsec, which seems to have a "sulk mode" where even swapping back a correctly configured router won't fix it. If anyone wonders why I'm messing with a working setup its because my existing router doesn't support ADSL2+ and objects to Win XP SP3

Draytek 2800 series seem to have some options that don't have equivalents on the 2600, but its still not quite as hard as Draytek to Billion.
I don't know how to make the 2600 respond to pings, it seems to default to high security but IMO the advantage of ping for diagnostics outweighs the security threst.