It is a legal requirement that you disclose your circumstances fully and accurately. Also, non-disclosure of credit commitments, missed payments, County Court Judgements (CCJs), accurate address history, and number of dependents will have a big impact on your application now and also on any future application for financial services (as evidence of this may be loaded onto fraud databases).
Disclosing any issues to a lender does not automatically mean the application will be declined – indeed many lenders have provision for this type of business.
You may wish to consider obtaining a credit report to identify any historical or current credit issues, as well as check your past address history.