Thanks to Douglas Myall, Deegam Publications I can now show you pictures and add to the post written on 31st July 2009 which described the Somaliland overprinted 1p Machins.
It seems that 95% of the information I wrote was correct. The Deegam Handbook describes, and illustrates two versions of this stamp, these are listed on page A15 - 67 of the Third edition supplement 2 appendix 15 of the Deegam CD.
For more information on the Deegam CD a link to his website is listed below.
Douglas writes " it was due to a shortage of special paper that the planned new Somaliland stamps were not issued on time and no printer in Africa could be found to undertake the contract at such short time.
It was obvious that some stamps had to be issued so the overprinted Machin plan went ahead. It was decided to release a small stock of these 1p Machins which had been overprinted 5oo shillin.
These were not favourably received by the local population and after a few days stocks were withdrawn and destroyed.
"The stamps were overprinted by letter press in somaliland and almost appear embossed from the gummed side."
Douglas states "that according to a press release most of the stamps placed on sale were for genuine postage, but a number were purchased by foreigners in the country at the time. About 30 genuine delivered covers were purchased from one of the government offices".
There are actually two versions of overprinted Machin. DG Number OM 64.1 - 1p Machin 500 shillin (no star) and OM 64.2 - 1p Machin 500 shillin with an additional star overprint. This is the same stamp as Harrison Machin 1p DG 10.24.1 with AB phosphor.
12½ sheets (2,500 stamps) had the star overprint and 9 sheets (1800) had the star omitted.
Learn more about the Deegam Handbook