Plotting charts approved in ICAO 007.
Ipads have not been certified for use in UK registered aircraft. The process for certification of commercial equipment is long and very expensive (before you install a £300 bit of IFE in an exec aircraft you will pay in excess of £10,000 for all the required testing). Significant kind of stuff like flammability / battery fire risk etc.
Like I said this kind of system is the future no doubt.....but I always consider what I am going to say to the investigator when the **** has hit the fan as my start point.