It's a motor vehicle. Under government rules they're entitled to keep it until a licenced and insured person comes to collect it, which will be half past never.
It's more interesting that the piece claims the dibble returned one to him on an earlier occasion, although this is local chipwrapper reporting. It does seem unlikely that the police would risk themselves being themselves prosecuted for use, cause or permit offences if Johnny Scumbag went straight out for a ride on it.
This will go to Court and the Court will order the scooter be destroyed, so Johnny Scumbag is going to learn an expensive lesson.
Ah, S17 PACE. Brilliant bit of legislation, the ways and means act. Too many barrack room lawyers get their legal training from US TV shows and think the dibble need a warrant to scratch their own behinds, when in actual fact it is rarely the case. That complaint ain't going anywhere.