Just as an experiment, I ordered some plastic plugs from a company 'Ross Handling Ltd' and fitted to the new GS at a cost of £17 + P&P
Whats the verdict
The plug in the oval hole under the seat needed a bit of trimming..
Just as an after comment,
The two directly in front of the cylinders on my bike popped out after a run. I believe the air heating up behind the plug pushed it out. Drilled a very (very) small hole to allow for this.
Exactly - if you are going to fit these things take them out before washing the bike and make sure the holes are thoroughly dried out before refitting them - they look good but too much hassle for me.