UKBA have announced a review of English Language test providers ( which will include A1 test providers for settlement visas). An amended list will be introduced by next April, and the changes won't affect anyone applying for a visa or Leave To Remain before 6th April next year ( 2014). This is the announcement :

Re-tendering exercise announced for secure English language test providers

A1 test providers change from April 2014

15 April 2013

This summer (2013), the Home Office will carry out a re-tendering exercise for approved secure English language test providers.

The re-tendering exercise will ensure all approved providers offer a high quality service, with secure and consistent tests and testing arrangements. It will also enhance the security requirements and establish more robust criteria for the administration of English language tests.

The re-tendering exercise will affect secure English language tests for:

Tiers 1, 2 and 4 of the points-based system; and

Spouses and partners of British citizens and persons settled in the UK.

For details of the re-tendering exercise and the mandatory requirements organisations must meet, please see our commercial partners page.

Information for applicants

If you are currently applying to take a secure English language test with one of our approved providers, these changes will not affect you if you apply for
leave to enter or remain before 6 April 2014. Changes to the list of test providers will happen on 6 April 2014.

Edited April 16, 201313 yr by ThaiVisaExpress

So could this mean that if one of the current test providers in Thailand were "struck off" then anyone applying for FLR after April 2014 with a pass from that test provider then they will have to redo their English test?

Actually I think this happened before when one or more test providers in Pattaya were "struck off" and I believe someone in this forum on a fiancée visa had a lot of trouble trying to get Leave to Remain with a test pass from one of the Pattaya test providers.