Rewire Security.
The 104Pro is a great bit of kit, can be hardwired so will kill ignition if vehicle is stolen, or simply recharged every 3 or 4 weeks. About £90 each unit.
You'll need a sim - they use giffgaff which uses a few pence a month.
The important thing is mapping - they use their own gpslive app, which says when your vehicle moves and gives its live position.
You could have both vehicles on same map.
Good thing is that they are an actual company who design manufacture and sell their own products, not simply a rebrander/importer from china.