"Y Llyfrgell" - Diolch John. @johnwilliams_6 Mae'n wych!
Just watched with the Welsh subtitles. I need to rewatch with the English ones (and/or watch the English version) sometime to catch the subtleties.
I'll try not to give any spoilers, but the Mam of the twins was played by Sharon Morgan, who played Dr Margaret Williams, Home Office pathologist who worked alongside the police murder team in "A Mind to Kill" (and seemingly the love interest for DCI Noel Bain (Philip Madoc) although it hasn't quite caught fire so far as I have watched.
Was Dan, the younger security guard a northener? Even so, I found him very hard to understand. Must have been an obscure dialect!
Phew! Quite dark! (but aren't most of these Welsh dramas quite dark....? ).
Wedi argymell! (recommended!).