In reply to Sharp:
Speak to builders, gardening business (preferably the designer type ones removing established gardens and replacing with minimalist garden designs) or farmers and you should find a source of topsoil or other suitable material. Usually lots of free (or cheap) topsoil to be had given the landfill costs so there for the effort of taking. Unfortunately it is often fly tipped alot. Remember that it does not have to be best quality topsoil if you want to take time and effort to make it better.
Other options for quick(ish) fix include manure (cattle/sheep/chicken/etc as long as not wood chip or sawdust based), old straw/hay (often dumped by farmers/horse stables/etc, but needs work/additives though to break down quickly), spent mushroom compost, lawn sods (lots did up lawns as too much effort to maintain and makes great soil after a couple of years), Local Council's composted material (some give away for free the recycled garden material that was collected others charge), coarse sand (if you have clay or heavy soil anyway and helps to improve it), peat bales (if you do not mind the environmental aspects and using lime and other stuff to balance it), coarse rubble/gravel (take out the soil and use as a sub soil esp if drainage problems), even sub soil (put underneath of course!) or take time over a few years and use your own/your neighbour's composting material to make it up to the level required.
