I tried changing the ICP/PBX addressing, then changing it back, no luck.
tried rebooting routers on both side, no luck
I can ping both devices FROM the other device via maintenance commands. I'm no packet monkey, but IMHO connectivity is connectivity *shrug* in fact I am accessing the web console of the remote unit via the VPN (either direct via web, or by RDP'ing into a server on that side and using web there)
I'm supposed to have the local mitel service providers coming by tomorrow to fix it, I will be watching carefully and reporting back here.