The Tower Hotel, Travel Lodge or The City Hotel are bang in the middle of town. The Tower is actually within the walled city...
A slightly cheaper alternative is Da Vinci's which is about a 2 mile from the city centre. a Fair walk if full of beer and meriment.
Highly recommended is The White Horse but that is a fair bit out of the town...
Let me know if you need any advice as I am a local but no longer living local....