I have rented a place before without having a previous landlord reference. You can only be upfront and open about it. Hopefully the landlord may trust his/her instincts and if they get a good vibe from you they won't let it stand in the way.
The fact you are self-employed is a complicating factor. I would show something to prove it. Many landlords place more importance on the work reference, as landlord references are easily forged (all you need is a mobile number and a willing accomplice).