OK, for the doubting Thomas’s, I’ve gone back and found the information covering the day limit in country. In fact the wording covers 90 days in 6 months rather than 180 days annually.
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-faq
The wording is as follows:
Furthermore, foreigners who enter Thailand under this Tourist Visa Exemption Scheme may re-enter and stay in Thailand for a cumulative duration of stay of not exceeding 90 days within any 6-month period from the date of first entry.