Currency valuation chart

I have received assignment related to financial management i share a case study so kindly recommended me how i tackle this case study it is benefit for those student currently doing P4 detail is as below

1. Currency valuation chart from September 2008 – November 2016

Note: Include, devaluation, increases, inflation within the UK, basically we are wanting to ascertain the investment we made of a one million pound in September 2008, which will double by November 2016, after considering everything what will be the true ROI.