Hi,
Please refer to notice 701/30 section 9, regarding supplies of English as foreign language:
English as a foreign language
For a commercial provider the conditions in section 9 need to be met in order for a supply to be treated as VAT exempt.
The place of supply rules should also be taken into account when determining whether you ae making a supply that falls within the scope of UK VAT or not. Notice 741a provides details on place of supply of services:
The place of supply rules for services
Thank you.