Instruction Sought: Commercial Debt Recovery, England and Wales

What I am looking for: I am a US-based media and creator economy company owner seeking to instruct an English solicitor to recover an outstanding sum owed to my company by a UK-resident individual under a written agreement governed by the laws of England and Wales, with exclusive English jurisdiction. My objective is resolution at pre-action stage. I am looking for a solicitor that can get a paid through a small number of well-judged, forceful communications before considering litigation. I am paying on a fixed-fee or hourly basis. I am not seeking a conditional fee or damages-based arrangement. The file includes the written agreement and the other party's written acceptance of it, the cost schedule that party prepared and supplied (authorship and version history preserved), bank records, written messaging evidencing payment agreement, an open settlement offer she neither accepted nor countered, and the complete correspondence chain.