Older lawnmower wont start - needs repair

Looking for someone experienced with small petrol engines or lawn mower repairs to inspect and hopefully get my older Masport mower running again. It's a Masport Quantum/Procom 500 Series mower, fitted with a Briggs & Stratton 4.5HP I/C Industrial/Commercial engine with a cast-iron bore. The mower currently won't start, but otherwise appears to be in good condition. It's an older, solidly built mower with a quality engine, so I'd prefer to repair it rather than replace it if possible. Looking for someone who can diagnose the problem, carry out an affordable repair and give it a basic service if required. Ideally someone with experience repairing older Briggs & Stratton engines. Happy to discuss a reasonable price.