Share some pictures if is possible. If this is true, you may add oil with small funnel and part of hose. There is no impossible things.

 

If i understood correctly - in R1250 GS with touratech bars like these there is no issue.

 

The Photos show pretty clear access to the filler plug, Touratech might mean the access to 719 Option filler plug is a problem. Is the filler plug on the 719 Option in a different location to the standard filler plug.

 

Have installed the Touratech crash bars and yes they do make access to the oil filler plug difficult But not impossible, I modified the plug tool that came with the bike which works.

 

Interesting. Do you happen to have a pic of the modified tool that will allow access to the oil fill cap?

 

I cut the end off the one in the tool kit and use a pair of pliers to loosen the filler plug then use my fingers to screw out the rest of the way.

 

The things people do... for the next one of you that comes along, get one of these or a 3d printed one - don't go chopping up bits of the onboard tool kit...compact oil filler cap removal tool

 

I got one of these on ebay, even better tool for the tight clearance with these crash bars.

 

I ended up getting this combination in China, works real well, no leaks from the cap. The new slim oil filler cap replaced the 719 cap.