let me know how you get on fourwinds. unlike merrick i've been out and about the past month in the neighbouring county of breckonshire (to the left of carmarthenshire) with my own book half written with no ideas about finding a publisher other than looking for a local one.
portal dolmens are a bit 'here be monsters' for me as breconshire consists of only hybrid severn-cotswolds. most of them had cairn coverings. the beast like pen y wrlod long cairn, talgarth still stands in places up to 3m high and is 55m long. their solution to cairn slippage was inner and outer retaining walls.