Regarding the 1926 with "pattern" reverse. It seems to be a hybrid of Freeman reverses B and C. It has the slightly larger figure of Britannia as on reverse B but has the border teeth of reverse C which are slightly longer and fewer in number (184 as opposed to 187 on reverse C. I assume that it's an interim stage of development of reverse C. It was sold at London Coin Auction in March 2009 as part of the Roland Harris collection (as a 1926 M.E.) and was previously part of the Andrew Wayne collection sold at LCA in June 2006 (as a 1926 M.E.). Neither collector seems to have recognised the non-standard reverse but it was later brought to my attention by another collector who had spotted the difference from the catalogue. I bought it shortly afterwards at Croydon Coin Auction in May 2010, again as a normal 1926 M.E. penny having recognised it as the Roland Harris coin from the CCA website.