RE: Kindle Touch - Does it work in the UK? Answers Here
I think your problem is you are opening the menu from within a book. If you go to the home screen first, you should then see all the options.
Otherwise, you could do it all on the Amazon websites ...
The first step should be to log in on Amazon.com and go to the Manage Your Kindle section and then 'Manage Your Devices'. Next to your Kindle Touch make a note of the serial number, and then select 'Deregister'.
Now, login to your Amazon.co.uk account and do the same thing but choose 'Register a Kindle' on the top right of the page and enter the serial number.
Your Kindle should now be registered to your UK account.