bvgs, The LAA is probably the place to start.
Their website says ... "We are a not-for-profit association, owned by our members, providing airworthiness services under direct delegation from the UK’s Civil Aviation Authority. We represent the aviation interests of over 8,000 pilot, amateur builder, vintage aircraft owner and enthusiast members, providing sector-leading consultation and lobbying on UK and European aviation regulatory matters. With over 2,500 operational aircraft, including 500 microlights and 100 autogyros, and another 1,700 aircraft under construction, our technical competence is second to none, worldwide."