Splitting shares

How companies arrange their dividends was examined by Mike Thexton in Scrip DRIP CRIP. I have come across a variation which was not covered there and I am not sure how to deal with it.

Aggreko plc reorganised its share capital in July 2011: a holder of 32 ordinary 20p shares received 31 new ordinary shares each with a nominal value of 13  p and 32 unlisted B shares.

There was a choice: the B shares could be purchased by the company for 55p on 11 July 2011 presumably triggering a capital gain; or the holder could elect to receive a 55p special dividend on 19 July following which the Bs would become worthless deferred shares; or the holder could retain the B shares until 2012 whereupon there would be an expectation of a later buy-back at 55p together with a...