I've got it working a bit better. Still some bad deformation especially when I did a test anim.
The first image shows the whole character and the second shows just the collision object after doing a "start local simulation"
My collision object is just a duplicate of the character's smooth skin, but with the arms and head deleted as I thought that they were causing unwanted deformations.
I'm not sure if that is a common way of working or not.
I need to play around with settings like offset to get the apron closer to the skin, but the problem is that when the character is animated the straps start to go through the skin.
Would it work if the the straps were extruded to give them some thickness, at the moment the apron is just one layer of polys.
In the docs it talks about the collision shape node having an attribute called Cloth Collisions, which can be used to help untangle cloth objects. Sounds useful but I can't find this.