sussex is a bit far from me, post any questions and ill help with what i can (its mostly the wiring side i do and fabrication for modifications. for new installs i usually work with a few fabrication companies who do the mechanical side)
also, im sure youre aware they have their own regs (12635, 12445, 12453 & various others), and if you leave a gate in a dangerous condition and something was to happen...