Skillsheets have some rather nice, completely free, Functional Maths PPTs/PDFs based on driving. (Select 'Functional Skills' and then 'Samples'.)
One is based on data handling and looks to be aimed at L1-2. The other focuses on units and is aimed at E3-L2.
There are also lots of other very useful maths worksheets – available as printed photo-copiable books or on CD. These include a three sets of Functional Maths sheets (E3, L1 and L2) plus pre-Entry maths worksheets. Sample pages are available free of charge or you can purchase books or CDs from £15 per set.