Have you enquired about free transport from your local LA or enquired about fuel costs or direct payments to cover the cost of fuel (From memory we get 12p per mile), which would offset the 5ppm surcharge?
With you next order due ext week, it will be less of a concern, but with the governments recently announced changes to the scheme, Motability are looking at ways to offset these changes and there are whispers going around mileage will be reduced to 10,000 per year, which will have a knock on effect with your next lease in 3 years time, if mileage becomes one of the changes.