BBC Wales website (referred to earlier) identifies G-KARE as one aircraft connected with these activities.
"The plane they flew on - a Pilatus PC-12 single engine aircraft with the registration G-KARE - is operated by a company called Flexifly Aircraft Hire Limited, based in Surrey and linked to a care home provider."
Company details identify Dr. Karen Graham as a director, thus the registration probably relates to her name. She appears also to be connected with Graham Care Ltd.