Kipper, you dont have to remove the seat just to replace the handle.
it just pushes in and you twist the black block at the top end of the cable to secure.
I broke the handle when i had the seat out replacing the cable but i didnt replace it with the new one till the seat was fixed back in.
Sometimes its not enough just to read instructions, but you have to ask for help too. I made a few mistakes when i first tried it(fed the cable thru from the bottom, broke the handle clips etc).

This thread helped me and saved me money that arnold crook would quite happily have fleeced from me(claiming it was a couple of hours job).