Hi Alexkara, thank you for that tip also. However, I have had a few goes at trying to get a handle on SketchUp and I cannot seem to master the concentration required to get a result worth anything. Most of my trouble is my lack of patience. But, with your prompting, I will put some of my holiday leisure time into a better effort of understanding the 'ins and outs' of SketchUp. Might work this time.
Cheers, Fred