One or two small things. Is she using the TalkTalk supplied router or an older one? Didn't see that mentioned because if it's not ADSL2 compatible then it won't go any faster.. Also, If she has just switched she may still be on 8Mb. IIRC when I switched, my voice line was switched first and later the BB went over.
I could still connect using my TalkTalk details but only got 8Mb. After they changed my BB to full llu I got the increased speed....