SPF issues (help appreciated)

Dear Sir or Madam,

I am the co-founder of ukmedicalschools.com and I'm hosting it from my Plesk-administered server (version 9.5.2). I'm new to Linux and Plesk so learning slowly.

I've set-up an IMAP e-mail service using roundcube and noticed my sent mail was being referred to the spam / junk folders of any external mail provider (E.g. hotmail, Gmail etc... basically anyone). In relation to this, I've learned that I need to setup an SPF TXT record on my domain's DNS zone (ukmedicalschools.com) which I've done - information relating to this is provided below. However, after doing this using Microsoft's SPF tool (http://www.microsoft.com/mscorp/safety/content/technologies/senderid/wizard/default.aspx) my SPF record is still not detected. To try and rectify this, I also ticked the box within 'Mail preferences' of Plesk to 'Switch on SPF spam protection', selecting 'only create received headers - never block'. Moreover, I have rebooted my server and restarted the DNS zone services (service named restart via SSH) many times.

In summary, I'm trying to create an SPF record for my domain, ukmedicalschools.com. Despite updating my DNS (and even waiting > 48 hours on occasions) for this change to take effect, external SPF-checking websites say there is no SPF record detected.

The same IP address for the server refers to all services hosted for ukmedicalschools.com
My mx(10) record is mail.ukmedicalschools.com
My current SPF record (though none of the attempted 'types' seem to have effect) is



My server-wide mail settings (At present) are (not I've unchecked the domain key options many times and still not worked, so got them on at present).



Since I'm just a learner to plesk and linux, I would appreciate and respect any kind help offered.

With kind regards,

Christopher