It is the student's responsibility to get the latest information on visa procedures and to complete the required documents. You should get all your documents related to the school by making the necessary initiatives from the relevant departments of the universities. The only document that the Erasmus Office will provide is the document stating that you are ERASMUS STUDENT. All students (including Green Passport) are required to obtain a visa suitable for their activity. A minimum of 2 months is required for visa procedures.
For a UK visa, a COS number must be obtained by applying to the British Council. Early application is important as this process takes at least 4 weeks. (Information below)
You can find consular information below to help with visa procedures within the scope of Erasmus Mobility.
Consulate General of Germany in Istanbul
Students who will go to United Kingdom with Erasmus Traineeship mobility must apply in the Tier 5 (Temporary worker - government authorized exchange) category.
About Online Application:(https://www.gov.uk/tier-5-government-authorised-ex...)