I heard there had been a couple of occurences of pilots who had filed nalax-rimto requesting nalax-otr, then not fully understanding what service they were receiving from the mil controller, as www says. Over the last couple of months, more and more flights have been filing via rimto. If you're unable to file via OTR, request a more direct routing with London on transfer from Maastricht. Depending on D323 activity and military workload (if you've not filed that way, they wouldn't be expecting to work you), you may be lucky!
You could also mention how many kilos of carbon you'll save.....
