D Wing 5.5 flying characteristics and briddle set up

i’m finding my 5.5 d wing a handfull to fly - even on the beach. it flies ok at zenith but as soon as it comes to one side or the other the wing tip curls under, and it falls out of the sky. I’m suspicious of the briddle not being right. It has the briddle config that is being recalled on the smaller sizes but which is supposed to be OK on the 5.5. However the yellow rear lines at either end of the wing are slack even when the rest of the yellows have good tension which seems to make it pivot round on the front corners. It flies better in stronger wind but still has similar issues. Anyone else having this - is it normal or something I should get adjusted. Have tried asking Flow but no reply..

The Flow 5.5 is a beast of a parawing. We have 2 of them at our local and both owners struggle with them. Just too heavy to fly well in the light wind and overpowered once the wind builds.
Others own the BRM Maliko 5.1 and have much better success, much lighter and easier to use. I swapped my 4.2 flow for the 4mtr BRM, so much nicer to use.