I’d write back and ask to do the course, you’ll still pay the fine but you won’t get the 3 points.
From Surrey Police website,
What are the speed awareness criteria for Surrey police?
The police will consider the following grounds when assessing your eligibility for the driver awareness course: your speed narrowly exceeded the limit and falls within the guidelines set out by the National Police Chief Council (NPCC) up to: 31 mph in a 20 mph area. 42 mph in a 30 mph area.
Please excuse spelling/typos. Apart from being a clot it turns out I had one on my cerebellum that's now causing various problems!