Well I decided after work tonight to make the modifications that Alan rightly pointed out needed to be done.
After looking a little more closely at the reference pics, I am convinced that this is an external panel sitting proud of the fuselage surface. So, I whipped out some thin plastic card and fabricated some panels. I also moved the rigging loops down to wing root level where the reference pics pointed out that they needed to be (even the Eduard instructions show these rings higher up).
I still need to touch up the paint work, but you get the idea...
Again, many thanks for pointing this one out Alan!
BC