I'd be very surprised if Humberside Police paid anything like list price for the ISF. In fact I reckon Lexus UK would almost give it to them as part of an image building/brand awareness exercise. They will be well aware of Volvo's sales success in the 90s when the police started using V70 T5s.
Also, rear legroom won't be an issue as motorway patrol cars rarely transport anyone back to the station - often single crewed only, they stop motorists and issue tickets and warnings. At most you could expect to spend 15 mins sat in the back while the officer issues the paperwork or shows you the video of your violation. In the event of anyone being arrested they would call for a van to ship them to the cells for charging.

 

Sickkkkk, glad they don't have these here haha

 

you can buy slightly used ISFs now for 50k sometimes under, recession ftw