[senco-forum] extra time in exams for foreign student

Dear All,
     Can anyone help please? We have a sixth former who joined us in Sept from Nigeria, she is running out of time in her AS maths papers and I am wondering if there is a learning difficulty rather than a case of this being a second language difficulty. She writes amazingly slowly and meticulously - I imagine she has been taught to do this and getting her to speed up may be difficult - I'm not too sure of her academic history prior to Sept. Normally we can deal with this under the rule that if they have been in the UK for less than 2 yrs they have extra time to use a manual dictionary. Unfortunately she seems to have visited the UK (aunt in London) many times so her passport dates exceed the 2 yr limit. 
      I do not feel confident that if I were to assess her I could separate out the english as a 2nd language difficulties from a genuine learning difficulty which would allow access arrangements and want her to be assessed by an EP (money not a problem...) does anyone have experience of this? I did ask one EP a while ago and he did not want to deal with foreign students because of the language difficulties. I've just spoken to one we use in school and she mentioned the non-verbal elements of the WISC and speed of visual processing but wasn't very confident that she could come up with an assessment which would prove the case for extra time.
    I am also conscious that once one of the foreign language students is seen to be having extra time after the 2 yr limit I will be inundated with request from the other forieign students who can be very demanding.
    Any ideas anyone? or a name of an EP who specialises in this area - we are in Shropshire but she does go to London.
    Many thanks,
  janet