The element with the least forethought is having to show an ability to converse in English with a candidate who may not be able to speak English. My partner was teamed up with a lady who was on her 4th attempt - the level of stupidity here is astounding. When she then went on to sit the GESE test in the UK she only had to talk with the examiner (who by her position we can assume speaks English) and she passed first time.
Not only that, the language used in the GESE test was the sort of conversations you would expect to have in day to day life, whilst the IELTS tests was expecting my Thai gf to have a conversation about mountain climbing in Austria. If the GESE test is an option take it.