SANS measurements of the vortex lattice allow information such as the penetration depth, coherence length, and the superconducting gap structure of a superconductor to be extracted. Intrinsic vortex lattice arrangements in the iron-based superconductor Ba1-xKxFe2As2 (BKFA) have been established as a function of field up to 16 T, on a high quality mosaic of crystals. The vortex lattice signal strength remains strong up to 16 T, and we wish to use the high field magnet at HZB to explore the higher field region which holds promise of exhibiting further unexpected behaviour which can help explain the underlying physics of the vortex lattice. In particular, we wish to see if the odd high field behaviour seen in YBCO is reproduced.