Be careful always not to commit inadvertent defamation- as yet, you cannot prove fraud, so don't allege it until you have clear evidence.
Things to do:
1. Verify what details HM Land Registry has for you as owner of the leasehold flat- e.g. your correct home address. Perhaps ask for an anti-fraud notice: see https://www.gov.uk/protect-land-property-from-fraud
2. Also check with your bank.
3. Yes, look too at your Credit File. Try Equifax and/or Experian.