My pension income total has not been reduced by the chosen split pension amount although this has been added to my wife's pension income . how can I fix this?

When you split your pension with your spouse, you will still see the full amount of the pension you received on your tax return as Pension Income on Line 115. 

Then further down you will notice the amount you are splitting with your spouse is deducted in the next section to arrive at Net Income (Line 210 - Deduction for Split Pension Amount).

Your spouse will have one entry on Line 115.