Hi Steve,
Sorry for the delay in reply.
I have put the steps below on how to create this wall type.
1. Open up your SketchUp file
2. Go to the PlusSpec tool bar and open the Wall tool.
3. Go to construction type and select 'Multi-Skin Wall'
4. Go down to materials and you will see all the parts of the wall that you can edit.
5. The first option is your external leaf. You will notice that there is no stone so we have to create a stone material and give it a 100mm width.
6. Select Create Material under the first option. See Screen capture below.

- Create Material.jpg (53.93 KiB) Viewed 6083 times
7. Now I dont know what stone you are after so I have just grabbed a stone seamless texture from a site. Find a stone seamless texture that is as close to the one you need as possible or go to your manufacturers website and they might have one.
8. Now go to 'Choose File' and find your image that you have just saved. See screen capture below.

- Choose File.jpg (17.09 KiB) Viewed 6083 times
9. Now choose a texture width and height for your texture.
10. Choose your name, brand and wall thickness and then select create material from template.
11. Now you have created a material that you can use on your wall. Go back to SketchUp and select 'SYNC' on the PlusSpec Toolbar. (This will download your material so that it can be used).
12. Now go back to your wall tool and select your new material that you have just created. See mine below.

- Selecting Created Material.jpg (61.04 KiB) Viewed 6083 times
13. Now you do not have to worry about the next 2 parts, Brick hardware and the Flashing.
14. Go down to the 4th option that will most likely say Bradford Soundscreen. We once again are now going to click create material but under the 4th option.
15. You will notice that when the webpage opens that there is no where for us to enter in our Width. I am going to show you how to do this.
16. We are going to edit the link. We want to remove everything after the = sign and replace it with b155c1ff-ed2c-480c-aeae-4c7382329922 . Check screen capture below for more details.

- Replacing Link.jpg (99.57 KiB) Viewed 6083 times
17. Now you will notice that red Rubys will appear and so will the wall thickness option. Just go through and do the same as we did for the outer leaf but make the wall thickness 100mm and find a seamless block texture. Then go and fill in all the options and click create from template.
18. Now we once again go back into SketchUp and click on the 'SYNC' button.
19. Go back into the wall tool and go down to the 5th option that will most likely have a 10mm insulation. Click create material.
20. Once again go and find a texture or colour for your insulation and find it using Choose file.
21. Go through and fill in all information and make sure to put the wall thickness as 170mm.
22. Click 'Create Material From Template'
23. Go back to SketchUp and select 'SYNC' again.
24. Back to the Wall tool and will now select the 6th option which will say plasterboard. We are going to click 'Create Material'.
25. Now find a texture that you want to be your internal finish. Once done fill out the options again and make sure to put width as 30mm.
26. Click 'Create Material From Template' and go back into SketchUp.
27. For the last time select the 'SYNC' button and go into the wall Tool.
28. Now in the wall tool go down to ‘Manual Overrides’ and make the cavity 220mm.
29. Select submit and draw your wall. It should look similar to mine below.

- Custom Wall.jpg (97.75 KiB) Viewed 6083 times
Please note that you will not need to do this every time just the first time. Your materials that you have saved will stay there.
Hopefully this is what you were after. Enjoy!
Kind Regards
Dean