There is no writing/spelling in IELTS Life Skills A1 - just speaking and listening. The most common reason for failing is if they get the listening questions wrong. The level of grammar required at A1 level is very low. It's basically just the ability to communicate with other people that is tested.
Thanks Tod. On another well known ThaiVisa forum, they're saying the opposite, as the graphic for Muang Thong only refers to Notification of Residence. I'll head to Muang Thong next week.