I can't even remember the last time I used a keepnet. Unless you are match fishing, or specifically want to stop fish returning to the shoal in a river whilst you're trying to catch more, why use one? Actually, even on the last point I still never use one, I'd rather release straight away. Fish handling is the main thing, whether using a keep net or not, especially with big fish. But additional handling through using a keepnet is still best avoided in my opinion.
I know you love barbel really Stewart. You just can eat a whole one