I am looking for a Blog to use on www.notar.co.uk. the site is static at present and I want to have this "information portal" managed via a blog. which one should I use ?
You should ask in the blogging forum... there's already a lot of feedback posted there on various blogging platforms.
Most people recommend the WordPress option hosted on your own domain. You can get a lot of free WordPress themes and it has good functionality compared to some alternatives.