You have to read the wording of the statement very carefully;
Splits are usually announced as "a ratio of X-to-Y"; meaning every X number of shares will become Y. E.g., 1-to-4 means, every one will become 4.
Bonus shares are announced as "X for every Y" held; meaning you get X additional shares for every Y that you own. E.g., 4 for every 1 means you get 4 in addition to the 1 making a total of 5.
Now, the Barclays announcement is confusing; it says "ratio of 4 for every 1 held". This can mean what @lovely2010 [will you change to lovely2011?] thinks; i.e., you get 2,000 new shares plus your original 500 to make 2,500.
However, the announcement goes on to say that the Par value of the shares will be changed fro Sh2.00 to Sh0.50. Now with 500 shares, your are holding Sh1,000 of the company's share capital [@hello; par value is the amount of share capital represented by one share].
When the par value changes to Sh0.5, you will have a total of 1,000/0.5 = 2,000 shares. This now agrees with @Amollo's argument.
Nevertheless; the wording can be challenged during the AGM just to make sure they consult grammar experts before releasing the announcements.
Nothing is real unless it can be named; nothing has value unless it can be sold; money is worthless unless you spend it.