AFAIK it is practically impossible to insure trade tools that are stored in a vehicle and even where cover is offered the premium payable would be extortionate. Your best bet is to secure the vehicle as best as possible, have a good alarm fitted and where possible keep the tools out of view. The gardai (in fairness) do recover a lot of stolen plant, tools and equipment every year but unfortunately they cannot return a lot of it to the rightful owners because the tools are either not identifiable or the owners have not recorded the serial numbers. So invest in a cheap engraver to mark your gear and spray with car paint and a stencil.