That will be an issue mate but not insurmountable, however a diagnostic tool will be needed to do a standing forced regen. Most obd generic tools can't do that, you need a higher end one or Lexia / DiagBox. I'm in central Scotland so plenty of motorways but normally congested. If your filter clogs completely, you will not be able to drive it anywhere tho. Needs sorted asap.
Onto the eolys tank, that's what the code for filter additive low meant. The 58 plate doesn't have that, only the 12 plate. It's a tank thing bolted into the underside of the van with a bag attached that holds the additive and a pump inside. Mine is reporting still at 50% but I've only just hit 61k miles from new so I'd expect that. Unless you are handy with the spanners and can get the van up on a lift, or at least high enough to work on comfortably, I'd maybe take it to a garage. The eolys fluid can be bought online but I think on these vans you buy a replacement bag and connect it to the pump unit. I guess it could be refilled but may be tricky, not tried this. It's the short lived forerunner to adblue which just goes in a filler cap beside the fuel filler. Eolys is not added in that way unfortunately. The bag holds 1 litre.
Do you have a garage you trust who can do all of this? Otherwise it will end up potentially off the road in limp mode if you keep using it till the filter clogs and the bag is empty.
I've had plenty of diesels with dpf filters, but this is my first with an eolys bag too. From what I understand it unbolts from the underside with one or two bolts and you replace the bag and refit. Might need the BSI reset to tell it the bag or tank is filled again. (Not trying to be a smart ass, just what I've read about the eolys additive system)
One more thing, it can be a plastic tank and not a bag, depends on exactly when they changed it over date wise, and the fluid is eyewatering price. And is a very nasty chemical...read this thread about it:
http://www.berlingoforum.com/thread-14058.html