Complex sentence: The company's royal connection was cemented by the appointment of Mappin & Webb's master craftsman in 2012 to the position of Crown Jeweller, the custodian of the British Crown Jewels and is responsible for preparing them for the State opening of Parliament and other state occasions.
Split into simpler sentences: The company's royal connection was further cemented by the appointment of Mappin & Webb's master craftsman in 2012, to the position of Crown Jeweller. The Crown Jeweller is the custodian of the Crown Jewels and is responsible for preparing them for the State opening of Parliament and other state occasions.