Do you mean the English language proficiency test? Or the test for the R/T license?
If it's for the R/T license, most flying schools will be able to help, as they have examiners who test PPL students for this test regularly.
If it's the English language proficiency test, then do you think you are Level 6 English? If so, any flight examiner can sign you off... if you can get to Bournemouth airport during the daytime, or to my home near Popham in an evening, I'll do it myself, but if you go to any flying club they will be able to put you in touch with someone.
If you are not Level 6, you will need to be assessed by a language school.
This document on the CAA website gives links to language organisations that can put you in touch with such a school, and also suggests a couple of schools. Oxford Aviation Academy can also do this assessment for you.
FFF
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