Dont know about ielts but CAS
Visa letters have become obsolete
From today, all potential Tier 4 students applying to us from inside or outside the UK must use a confirmation of acceptance for studies (CAS) in their application. All applications that do not contain a CAS will be automatically refused.
Sponsors must now provide all potential students with a CAS reference number and sponsor licence number (SLN). You will also need to give them all the information they will need when making their application. This information is sometimes called a ‘CAS statement’; it is up to sponsors to decide its format and how to send it to their potential students. A ‘CAS statement’ may contain:
- student name;
- student date of birth;
- course title;
- course start and end date;
- details of any financial sponsorship/deposits taken;
- documents that should be included as part of an application to prove qualifications;
- CAS number; and
- ATAS certificate (if appropriate).
This additional information will assist our caseworkers and entry clearance officers when making decisions on migrant applications under Tier 4.
If a prospective student has a visa letter issued before 22 February 2010, they can no longer use it to apply for a Tier 4 student visa. Previously issued visa letters not yet submitted must replaced with a CAS.
For out-of-country students, the date of application is the date when the application fee is paid – so a prospective student must be in possession of a CAS if they are paying their application fee today or later.
Mandatory reporting on students who have been assigned a CAS
http://www.immigrationmatters.co.uk/...-with-cas.html
Have a look on this site it may answer your first question
