Help SMS bringing up list of old numbers

[anpease]

A couple of my friends have changed their phone numbers, and I have changed the details on my Contacts.
However, now, when I select someone to send an SMS to, and the phone brings up a list of choices as I type the letters in, the list includes their old numbers as well as their new numbers.
I have sent the texts to the wrong numbers a few times by mistake.
How do I clear their old numbers from this as well?
They are still only in Contacts once, with the correct number.
Many thanks.

 

[Hawker]

You probably have the old numbers stored on your sim card.
go into contacts>menu>contacts to display and untick SIM

 

[anpease]

I have no contacts on my sim card at all (have backed them up to my PC), and have only phone contacts being displayed.
The old numbers are not listed there at all.
Would they be remembered in some kind of sms cache somewhere, which I could clean?
Cheers.