TikiBar, the way JAA work(..ed. It's being replaced by EASA**) is to set requirements that member States must then implement within each State's own regulations. JAA isn't a regulatory authority in the same way that the FAA is.
This 'implement within own rules' thing has allowed different member States to interpret the JARs differently or . One of those differences is that the UK's Civil Aviation Authority allows the 1500 hours on heavy jets shortcut - something that other States don't recognise - so they're the one's to go through.
Contact the UK CAA to start the process.
**Unlike JAA, EASA will be the regulatory authority and will set the rules for the States to adhere to.