My Year 13 further maths group have diligently worked through all of the past papers (often more than once). To keep them going up to the first core pure exam (and to stop them getting bored!) I wrote two brand new practice papers, with solutions (this is for the Edexcel specification). I think the difficulty is about right but do let me know any thoughts!
Core Pure 1 Practice Paper (Solutions)
Core Pure 2 Practice Paper (Solutions)