Filter out (with TestFilter?) records starting with specified word

Hello Group,

I have a polygon dataset of LSOA boundaries read into FME. It contains a field called ‘LSOA21 2021 name’. The values in that field are entries like 'Southwark e09', 'Lambeth e08' and 'Lewisham e13'.

I want to filter out only those records where the value begins with the word ‘Southwark’.

I’ve added a TestFilter with an If Test Condition of @Value(LSOA21 2021 name) CONTAINS_REGEX Southwark. But that is maintaining the entries where LSOA21 2021 name equals, for example, Lambeth e08.

I’ve been looking through https://docs.safe.com/fme/html/FME_Desktop_Documentation/FME_Transformers/!Transformer_Parameters/StringFunctions.htm, but couldn’t work out exactly what string I need.

Any ideas, please?

Thanks,