If it's in for maintenance, it might need to wait a bit, there's a queue.
Neither Artful or Ambush at Faslane look like they are going anywhere soon
Ambush last at sea 1392 days ago. (3.81 years) Artful last at sea 1119 days ago. (3.06 years) Neither in an official refit, like Audacious which is at 1149 Days (3.14 years). Astute is in refit at 328 Days, with no dry dock yet available due to the former.
https://x.com/TBrit90/status/2058549690300297220