you'll have to get your installer to change the grid parameters as they will have to obtain a grid guard code to access the grid monitoring values, if its set to (a)5,(b)8 it will be set for uk with g83 compliant settings settings, that said i did have one that thought it was an sb5000tl and was not a happy bunny, so it might be a firmware c**kup, we had one which had to have the upper frequency cutout changed from 50.5 to 51.5 (western power) for this problem too.. bad news when the dno agree to specific values then move the goal posts... :-( when you find out what the problem was post it on here. what size system do you have is it over 3.68KWp?