Letter to ministers comes amid pressure for a more robust response to the Huawei leaks.
The struggling department store chain plans to close the shops next year, affecting 1,200 staff.
Working out what makes Charlie Parkes ill is like fitting together "little pieces of a puzzle", his mum says.
The blast came from a train used to carry molten metal at the Port Talbot site, Tata says.
The duke has been meeting survivors of the Christchurch mosque shootings, which killed 50 people.