Health kit: Remove phone as datasource for steps

I've got a 6 plus and have just got jawbones UP update to allow healthkit integration. I've set it up as a datasource for steps.

Problem is when the data from UP is not available, ie i've quit the UP app or whatever, the phone's motion processor starts logging steps. Next time I sync my UP band, those steps come across too and I get a double count.

I'd like to be able to turn off the iphone as a source for the steps data completely but can't see where to do this.

Anyone else have any luck doing it?

Cheers