OK, I am now 100% sure it's not Outlook causing the problem. I have set up a different email account in Outlook where the domain and mail servers are hosted by some other hosting company. It's a similar setup where there is a webmail facility as an alternative to Outlook. I received the emails into Outlook for this account straight away without any issues. I tried it with POP and IMAP and both work.
This leads me to believe that it has to be some setting on the hosting side that is causing the problem. I only started using webmail after my harddrive failed. Now having installed a new drive and Outlook I want to move away from the poorly built web client and back to Outlook. May be I need to somehow disable the webmail. I will look into this. The thing is when I switched to webmail from Outlook I never changed any settings, my emails were already accessible from there. So I am still confused. I'll post the solution when I eventually get there, but I am getting closer.
Thanks.