In 1922 a De La Rue/Onoto pen was offered to retailers on an 'own brand' arrangement, it was taken up, a good while later, by Boots and stamped 'The Chatsworth Pen'.  A line of Chatsworth pens were also produced by Burnham under the same arrangement. 

Finished in black with polished chrome trim, this is an extremely fine example.  It has an excellent surface, crisp imprint, and bright trim.  The clip carries the De La Rue 'sunburst' logo and the original nib size, a medium, sticker is still in place.  After around seventy years I was reluctant to remove it.

The pen is constructed in hard rubber, an unusual material for a 1950s pen.  It is possible that De La Rue were keen to use up all old stock left over from the move to plastics decades earlier.  There is no sign of the brown tinge that is usually present as the hard rubber surface oxidises.

A new ink sac was fitted and the pen was thoroughly cleaned, checked and tested.  The filling system works well and the 14 Ct. Gold De La Rue nib writes with a medium line and has a good flex that anyone with a decent 'hand' would enjoy.  At 15cm. when posted it is a good sized and well balanced pen. 

I would have said that this was a 1930s pen but, thanks to Stephen Hull's excellent 'Onoto The Pen' book, I have been able to track the pen down, I think, to it's roots as a 1950s Onoto lever filling ink pencil.  It is identical in shape and size, although the pencil appears to have a Gold trim.  The minimum order under the 'own brand' arrangement was one gross (144), a number that must have made it economically viable for De La Rue to make the necessary modifications to convert the ink pencil to a fountain pen. (see last photo)

Chatsworth pens do turn up for sale now and then but they are almost always the Burnham made variety, the De La Rue/Onoto version is much less common and is a higher quality pen.  This pen is clearly of collectable quality and condition but would also make a very unusual everyday vintage writer.