Many thanks for the "cool" comments - much appreciated! My son confirms that he also considers them to be cool, and he uses them which really makes me happy! I don't think that there is a much sadder thing than spending time to make pens that then sit in drawers.
I have attached four more images (thanks for asking Curly!) - two of which show detail of how they were made up. The pencil is a standard toolbox / artists pencil mechanism. The sharpener is fitted into an extension from the bolt head so that it can be screwed onto the mechanism and then pushed down to operate the pencil jaws. The pen is based on a Berea Atrax mechanism and tubes with the lower tube glued into the bolt. I'm using the same principle to make two differently themed items for my youngest (who is also an engineer and got me started on pen making). I'll post pictures once these are finished.
Thanks again - and hope we all continue to enjoy this fantastic hobby / craft for a LONG time.