The inner cap on my HS Bronze Age pen has begun to stick when I uncap the pen. When I remove the pen from the cap, instead of the inner cap immediately and smoothly releasing, there is a delay of a second or two, and then the inner cap releases, making a very audible popping sound. It sounds as though the inner spring mechanism is sticking somehow. Is there a way to fix this myself, or does the pen have to be shipped of to Coles of London? Thanks for any info......