Release Of Sale & Purchase Agreement Only After Receipt Of Reservation Fee

Came across these reservation terms on a new development.

Is this legal in Thailand?

1. Sign Reservation Form

2. Pay Reservation Fee within 10 days of signing Reservation Fee

3. Developer releases standard Sale & Purchase Agreement 7 days after receipt of Reservation Fee.

4. Sale & Purchase Agreement signed within 45 days of the date of the signed Reservation Fee ie 28 days after receiving Sale & Purchase Agreement.

Sale & Purchase Agreement is non negotiable and the Reservation Fee non refundable.

I think in the UK and US this would be illegal since the buyer has the right to be aware of all conditions governing the sale prior to paying a deposit?

Has the lawyer who prepared the terms and conditions broken any rule or guideline of the Thai Law Society by intentionally retaining information until the fee has been paid?

Comments please.

Note:

In this case the Sale & Purchase Agreement is extremely onerous providing the buyer 0% tangible security throughout the construction phase, not least requiring stage payments on the basis of time irrespective of progress.

No wonder the developer didn’t want the buyer to see the Sale & Purchase Agreement before accepting the Reservation Fee.