Moving to Thailand
To Thailand
A move works better when housing, school, and entry rules are read from current official pages, then written down together, rather than settled in three separate conversations.

If you are leaving the United Kingdom for Thailand, start with the questions that change the plan if the answer is no: can you enter and stay for the period you intend, can you rent a place that you have actually seen or that someone you trust has seen, and can the children start at a school whose current fee and admissions pages you have read?

Rents and school calendars are local. A figure quoted by a friend who left two years ago is a starting point for a conversation, not a budget. Ask a landlord or an agent for a written list of what is included (furniture, air-conditioning, parking, a sinking fund) and what is paid separately (electricity, water, internet, a security deposit). If a school run depends on a particular road or a rail line, travel it at the hour you would actually use it, or ask someone who already does.
Documents you will need at the other end (passport validity, a tenancy, school records, vaccination records if a school asks for them) should be listed before you pack. This page does not tell you which visa category applies to your household. That belongs on the official instructions for the category you think you are in, which you should read yourself.