Planning in town greenbelt for second property

Hi all,

I own a house within a town greenbelt. Near my house, a site has come up for sale (also within the greenbelt). On this site, there is an old disused cottage. I would like to consider buying the site and doing up and extending the cottage (and maybe live there). I have been told conflicting advice however on this. Some people I know are telling me that since I already own a house on the greenbelt, I would not get planning on that site because I don't have a 'housing need' and the planing is very strict in greenbelts. Others I know are telling me that since there is a house on the site already, I would have no problem getting planning to do it up and I don't have to prov this 'housing need'. Just curious what the consensus would be here?