Thanks for your reply, however I don't agree with the answer. Firstly, I couldn't get it to work and secondly it would mean a lot more programming just to replicate what I think should be default behaviour.
I took a look at the Microsoft Ribbon Licence document, which states that the contextual tab must not become selected when you are selecting an existing object. If creating a new object then the contextual tab should become selected. I have marked the sections in the extract below.
1116 1. Contextual Tabs MUST be available when the user selects an existing object in the document, **but the
1117 Contextual Tabs MUST NOT become selected. The currently selected tab MUST continue to be selected in
1118 the Ribbon**. This behavior is different from selecting the Contextual Tabs when a new object is inserted
1119 (as described in the section above). (Note in the figure below the Picture Tools Contextual Tab is available
1120 when the picture is selected in the document, but that the Picture Tools Contextual Tab is not selected.
1121 **The Home Tab continues to be selected in the Ribbon when the user selects the picture in the document.**)