I found this site so helpful when I started researching for my daughter. She struggled for 2 years to get a PCOS diagnosis (and treatment) because she wasn't obese and couldn't meet the criteria.
Found a specialist who easily diagnosed PCOS with a lab test for Antimullerian Hormone. Don't know if that's available in UK, but it's a simple lab test so it should be.
Good luck on your journey ladies, hope this helps some get support faster.