Historical share question

[Simpo Two]

Delving through some of my late mother's papers I see that between 1964 and 1997 she bought 150 shares in RDS. In 1997 new shares were issued at the rate of 2 for 1, so she then had 300. Now there are only 129. I don't believe she ever sold any, so was there another re-issue/re-valuation between 1997 and c.2010?

[Newc]

There was a total capital restructure in '05.