I've worked in board effectiveness for several years. This is a very different type of consulting, but highly valued, to that of the major consultancies and strategy houses. Your experience and skills, particularly being a Company Secretary would be of interest to the key players in this field. I would advise talking with some of the Board & Executive Head Hunters - Korn Ferry, Whitehead Mann, etc. Also try specialist firms like Mercer Delta in US (Not sure of their strength in UK?). Other forum members may be able to highlight some specialist firms working in corporate governance and board effectiveness. Good Luck!