I recently found out that there is a (state?-)tax-funded community resource in the US associated with Land-Grant State Universities called "Extension Offices". They offer soil testing kits, personalised advice and even officers who can help you develop your soil/garden.
(All this from a video here. Specifically @~0:40 and again @~1:48.)
Are there any similar resources in the UK that I should know about / make use of?