[MargaretR]

I have found a webpage quoting fees

Reclaiming Dogs

Aspen Valley is open Monday to Friday 10.00 - 17.00, and weekends 09.00 - 13.00, for reclaiming dogs, by prior appointment. Dogs only released once due fees have been paid.
Aspen Valley Kennels

Lower Aspen Lane, Oswaltwistle, near Accrington, BB5 4NY

Reclaim fee:

£60, plus £18 for first night, plus £8 for each subsequent night. Dogs held for 7 days before being destroyed or made available for re-homing.

If you have not been burgled the presumption is your son was negligent