RBS consent to let - deal ending

Hi there. I have a consent to let on a flat I bought to live in, but now rent out from almost 2 years ago. The consent does not have an expiry date. The fixed rate deal I was on is due to expire in April 2013 after which the mortgage moves on the the RBS SVR which is 4%. Firstly is it likely that RBS will contact me to try and push me on to their BTL deals or can I remain on the SVR? I assume that me contacting them to try and get a new residential deal is a bad idea because that will just alert them that I am renting the property - or is my mortgage still classed as residential and I am eligible for residential deals? A SVR of 4% without paying any fees is still attractive compared to the costs of buy to let mortgages. Wondering if anyone has had any experiences in this area or know what RBS policy is here?

Thanks
Sarju