Thanks for all your advice. I did as suggested and booked 3 nights at the Chancellor Hotel for £375, refundable.
I kept an eye on the price every month or so and it was usually around £450- 500. Following the devaluation of the pound I thought I was unlikely to get a better rate but last month I spotted a non refundable deal at £326 so definitely a happy chap.
I've stayed at the Chancellor before so know what to expect there. All booked through hotels.com
Thanks for all your help.