Bristol - Frankfurt is operated with a BMIR ERJ-145 and is bookable on the lufthansa website under codeshare. It's like Lufthansa operating the route without them having to bother themselves in actually doing it, essentially a few free passengers on their connecting flights every day... I can see numerous benefits in my suggestion, as BAladdy said it's pretty much the perfect route for their business model. Added to that the fact that increasing star presence at NCL can't be bad and may hopefully help UA down the line.
What is the story behind BMR/LOG, are they to remain as separate entities in a menage a trois with Flybe?