Chemical advice please

Ongoing conversation with a UK lawn specialist about Speedwell, has come up with this.

Benefin.   N-Butyl-N-ethyl-a,a,a,trifluoro-2,6-dinitro-p-toluidine (56)

I cannot find any reference to this in UK or connect it to a product we know.   Please can you help.  Mrs Bouquet

Thanks for your reply.  I wondered if it was a US only product, due to lack of UK info.    Ah well, I tried  Mrs Bouquet