Mate
Not good news, first up you will not get the Jar Class 1 medical with that prescription. I have been trying for years and mine is +5.50/+6.0. I'm told I can get a Jar Class 2 but they do not allow the same flexibility with long sightednesss than they do for short sightedness. I have comminiacted several times with the UK CAA about this and only in Nov did the medical rules get updated without any changes to the long sightedness.
I have a New Zealand Class 1 and would get an FAA one aswell but to get a JAR medical it doesnt make any difference, you start from sqaure one unless you have an FAA ATPL but even then it wont make the difference you need.
PM me for more if you wish
Sorry!