Yep, I sympathise with you. I got Galaxy S3 just on Tuesday so have been working my way through 'some' of the bits and yes, it's so difficult at times, isn't it?
As for typing Ashford, I've just tried it and after typing Ashf, it then came up with Ashford. So, not sure. Have you tried continuing to type in the letters and see what it comes up with? I've not already typed that town on this phone so I don't know why it came up ok on mine.
However, like you, I would like to know how to 'force' the required letters/text.
As for how to send a text, it seems you need to tap the little black envelope with arrow pointing to right, at the bottom right, beside the message pane. Hope that helps you on that bit...
Well, I hope you get to grips with it soon. I think it's a brilliant phone but will be even better when I learn how to use it!!! ;)