Nasturtiums for companion planting

As an experiment, this year I tried using nasturtiums as sacrificial companion plants to keep the cabbage whites away from my brassicas. I have a veggie bed that's about 18' X 18' surrounded by a 4' wire fence. I put climbing nasturtiums all the way round, growing up the fence. In the bed I have white, red, savoy cabbage, cauliflower, brussel sprouts and calabrese, and so far I've had absolutely no caterpillar damage or signs of eggs on them, only on the nasturtiums. I used no sprays and no netting.

I also had a few red cabbage/calabrese/sprout plants sitting around in my cold frame, because I ran out of space to plant them, and these have been absolutely covered in caterpillars. Maybe it's just coincidence, or maybe it really does work, but I'll be doing it again next year. Anybody else have any good/bad experience with this?

Ive just had a quick look at a book I got recently  - it mentions sage also for repelling cabbage white.  It mentions nasturtiums but nothing about cabbage white so nice discovery