You could probably find options just under a tenner. Check this place parcel2go.com, they have good options. Royal Mail is about £13 if I remember rightly. Somehow Juno charge about a fiver, I have no idea how they do it so cheap.
The guy quoted me 9 pounds for standard royal mail. I went on their site and saw 5 but I'm not sure of the exact input for a record so the 5 might be off.