OS Landranger, as detailed in SRs. Snake-lights are quite good too. A normal torch can be a bit tricky. Standard car interior lights can only really be used while stationary, for plotting. A small piece of plastic that is invaluable for plotting grid references.
Plastic ones are very good.
Rally time will be available at the start, so you can set your watch. Just in case. A square of cardboard to rest on. Handy if clock times are used. Grid references Usually given as six figures, e.g. 453576 is the Panton Arms.