With some quantification –
Listening to internet radio (64kbps- most common BBC – 128 kbps) = 30-60mb per hour. ie if that’s all you did you could listen to the radio for 12 hours a day every day and you would go just over your 10gb
Watching iPlayer – (best non-HD quality = 1500kbps stream) you’re using about 0.7gb an hour – 14 hours a month.
Emails without attachments are almost insignificant, web browsing stacks up more than you’d expect (people put some big images in threads on here) and operating system updates come regularly and can be multi-GB.
Try it and see how you go (check what their policy is if you go over) – you can always switch to a different tariff. Unlimited is cheap enough in cities but if your exchange isn’t unbundled (as i found out for my parents) there’s a lot less competition and costs are higher.