In addition to L1-2 past papers, AQA has a good selection of Functional Maths (FM) tasks for underpinning and practice. There used to be a very good 110 page PDF document with 30 challenging maths tasks written by Leeds University to support teachers in pilot Functional Skills centres way back in 2008! The document has disappeared from the AQA site but I've found Tasks for AQA Functional Mathematics 2008 on the Lancashire Grid for Learning :).
These pilot tasks provide a great overview of the required skills and the types of questions that will be asked for L2 Functional Maths. Each of the 30 tasks consists of a data sheet (this could be a short text, a diagram, a table of information, a graph, etc.) followed by a set of questions. Many cover vocational areas. Topics include: farm animals, solar system, bacterial growth, bricklaying, hair salon, digital prints, picture frames and kitchen design. The guide also includes a discussion about teaching strategies and commentaries on some of the exercises.
AQA also has a more recent set of straightforward single page worksheets aimed at L1-2 FM and Foundation GCSE Maths students. Worksheets have accompanying task sheets (for teachers) with ideas for starter activities (and worksheet answers!). Ten topics including beach bar, bikes, dog walking and Paris.