Thanks for that. I've never seen != before... I thought that <> was a universal not equal to, but hey, I'll give it a go.
Also, I've used the word 'blank' because the CMS solution doesn't allow for an actual blank entry in the database. I was hoping to use the two quotes, but unfortunately something has to be entered into the text editor to ensure that it submits to the database.
I would remove the validation on it, but I need it to be there for when the same page is working on other areas of the site.