Hi Aled
30,000 unique visitors a month is sadly not an accurate figure to work from, not even close...
You would be better off determining the actual data transfer/bandwidth usage and space, as this is a better indicator of resources.
Typically though, on our shared servers, this would not be a problem at all..
Our web hosting is classed as premium hosting, somewhat undersold if you like, but often saves people a lot of money, where others would push you towards a VPS (Unsuitable) or a server, with us, shared hosting in many cases is fine.
Our reviews are monitored independantly by ratepoint too, we dont write our own lol
http://ratepoint.com/seereviews/6424