Not a problem at all, unless, possibly, if the child will later on go to school in Thailand and require an Ed visa.

@Kai ******

Not if you've just returned to Thailand. It resets to 90 days after you arrived.

You don't need to do a 90-day report until 90 days after you returned to Thailand. Normally, fines are not imposed if there has been a public holiday.

I know. I arrived on 1 May. However, the field for the country of boarding is not important.

No. The TDAC is only needed for international arrivals

I put UK not UAE as we just switched planes in Dubai. It was fine. They don't even look at the TDAC at Passport control.

No. It's only for international arrivals.

Leave it blank.

@Myles ******

The rules changed as foreigners in Thailand need to have valid/ID. Thailand is one of only a few countries that allows you to retain your old passport during the process. It's also one of the only countries where the process is not online.

She will need a Settlement visa. You will need to meet the financial requirements, provide acceptable accommodation for her and prove the relationship is genuine. She will need to pass a UKVI English test at minimum A1 level and have a TB certificate. It's a fairly lengthy and expensive process, and that's just for the initial visa. For Leave to Remain and finally UK citizenship there a more tests and more costs.